Sentences: Structure, Verbs, Voice, Variety

To be effective, sentences in technical documents need to offer information clearly and succinctly in a way that’s easy to read and comprehend. Elements that help make sentences effective include structure, verbs, and variety.

Sentence Structure

Simple Sentences

The simplest of sentence patterns is composed of a subject and verb, an “actor” performing an “action.” You’ll use a lot of simple sentences in technical writing. However, that does not mean that the information is simple, or that you use a simplified tone. It simply means that the sentence offers its information in a very direct way. For example:

  • Control rods [subject] remain [verb] inside the fuel assembly of the reactor.
  • All amplitude-modulation receivers [subject] work [verb] in the same way.
  • The cross-member [subject] exposed to abnormal stress eventually broke [verb].
  • Folding and faulting [subject] of the earth’s surface are [verb] important geologic processes. (Note that sometimes a verb is a form of “to be,” such as “is,” “are,” “was.”)

Compound Sentences

A compound sentence is made up of two simple sentences joined by a logical connection. Make sure to include an appropriate linking word to show that connection as appropriate (e.g., and, or, nor, but, yet, for). Also make sure to include appropriate punctuation when linking two simple sentences: a comma + a linking word, or a semicolon and no linking word. For example:

  • In sphygmomanometers, too narrow a cuff can result in erroneously high readings, and [comma + linking word] too wide a cuff can result in erroneously low readings.
  • Some cuffs hook together; others wrap or snap into place. [semicolon and no linking word]

Adding modifiers and phrases into sentences

Modifiers and phrases more fully describe or explain ideas in sentences. A modifier is a word which explains other words in a sentence. A phrase is a group of words (not a complete sentence) that explains other words. Make sure to insert modifiers and phrases in places where they make sense and offer the meaning that you intend. For example:

  • You can then see a cable behind the cover made of steel. [this indicates that the cover is made of steel]
  • You can then see a cable made of steel behind the cover. [this indicates that the cable is made of steel]

Parallel Sentence Structure

Think of two parallel lines—they are the same length, and they maintain the same width apart. Likewise, when you want to include multiple similar items in a sentence, keep them in the same format (e.g., all -ing phrases, all past tense, etc.). For example:

  • This step involves disconnecting the coaxial cable and then reconnecting it after performing the update. []this sentence uses parallel structure, with “disconnecting” and “reconnecting” in the same format
  • This step involves disconnecting the coaxial cable and then you have to reconnect it after performing the update. [this sentence is not parallel, since “disconnecting” and “have to reconnect” are not in the same format]

Verbs in Sentences

Think of a sentence as a machine, and the verb as the engine that makes the machine work. Like machines, sentences can function efficiently or inefficiently; using a strong verb is one way to make them work effectively. Although effective sentences may occasionally deviate from the suggestions in the list below, try to follow these guidelines as often as possible:
  • Keep the subject and the verb relatively close together; avoid separating them with words or phrases that could create confusion.
  • Use active, descriptive verbs.
  • Used “to be” verbs sparingly (e.g., am, is, are, was, were, being, been, be).
  • Try to turn nominalizations (abstract nouns) back into verbs.
  • Prefer active verb constructions over passive ones.

Active, Descriptive Verbs

The most active verb type is a command (e.g., Replace this, Do that). However, you are not likely to use the command form very often, unless you are writing instructions. The second strongest form, Active Indicative, is the one you want to use most often (say, in about 80% of your sentences). Part of the skill of using active verbs lies in choosing the verbs that precisely describe the action you want to convey. Verbs such as “to be, to do, to get, to make, to have, or to put” are relatively vague and not very descriptive. Whenever possible, avoid bland verbs and use more precise, descriptive verbs, as indicated in the table below.

Bland vs. Active, Descriptive Verbs
 
Bland Verbs Active, Descriptive Verbs

Signal Verbs:

Says
States
Talks about
Discusses
Writes

Describe the rhetorical purpose behind what the author/speaker “says”:

Explains, clarifies
Describes, illustrates
Claims, argues, maintains
Asserts, stresses, emphasizes
Recommends, urges, suggests

Is, are, was, were being been

Is verb-ing

Instead of indicating what or how something “is,” describe what it DOES, by choosing a precise, active verb.

Replace progressive form (is ___ing) with  indicative form

She is describing → She describes

Get, gets

Usually too colloquial (or passive); instead you could use more specific verbs such as

Become, acquire, obtain, receive, prepare, achieve, earn, contract, catch, understand, appreciate, etc.

Do, does

Avoid using the emphatic tense in formal writing:

It does work →  it works.

I do crack when I see apostrophe errors → I crack when I see apostrophe errors.

Instead:  Perform, prepare, complete, etc.

Has, have

Has to, have to

 This verb has many potential meanings! Try to find a more specific verb that “have/has” or “has to”:

  • She owns a car
  • They consume/eat a meal
  • The product includes many optional features
  • The process entails several steps

Instead of “have to” try:  Must, require, need, etc.

Make

Build, construct, erect, devise, create, design, manufacture, produce, prepare, earn, etc.

Make a recommendation → recommend
Make a promise → promise
Make a plan → plan

Nominalizations

Nominalizations are verbs used as nouns. Verbs are stronger when used for their intended purpose, to show action. For example, in the following two sentences, the verb “maintain” has been nominalized.

  • Machine maintenance is a difficult job.
  • However, a well-maintained machine is a thing of beauty.

To find nominalizations, check your writing for sentences that use “to be” as the main verb and use a nominalization as the sentence’s subject. (Look for -tion, -ment, -ance, and other suffixes, and look for “of” phrases to find nominalizations.) Sentences that use nominalizations are often weak or indirect. Revise them by changing the nominalization into a verb and replacing the “to be” verb. Your sentences will sound more active, and they will be easier for the reader to understand.

Sometimes, you can’t convert a nominalization into a verb, or a nominalization needs to remain a sentence’s subject. (For example, “information” is a nominalization, but try converting “information” into a main verb. The sentence will be awkward, at best.) More often, though, you can convert that nominalization into a main verb.

The following examples demonstrate this problem and how to fix it. In each revised version, notice how a noun has been converted into the sentence’s main verb and replaced the original “to be” verb.

Nominalization Examples
Problem Sentence Revised Sentence
The contribution of Quality Circles is mostly to areas of training and motivating people to produce higher quality work. Quality Circles contribute to the training and the motivating of people to produce high quality work.
Measurement of temperature is done in degrees of Fahrenheit or Celsius, and its indications are by colored marks on the outside of the thermometer. Temperature is measured in degrees of Fahrenheit or Celsius and is indicated by colored marks on the outside of the thermometer.
The beginning of the clonic phase is when the sustained tonic spasm of the muscles gives way to sharp, short, interrupted jerks. The clonic phase begins when the sustained tonic spasm of the muscle gives way to sharp, short, interrupted jerks.
During speech, the generation of sound is by vocal chords and the rushing of air from the lungs. During speech, sound is generated by the vocal cords and rushing air from the lungs.
The response of the normal ear to sounds is in the audio-frequency between about 20-20,000 Hz. The normal ear responds to sounds within the audio-frequency range of about 20-20,000 Hz

Active & Passive Voice

In the simplest terms, an active voice sentence is written in the form of “A does B.” A passive voice sentence is written in the form of “A is done by B.” Both constructions are fine. In fact, notice how the sentences below, depending on the context in which they appear, are equally acceptable:

  • Passive voice: The rate of evaporation is controlled by the size of an opening.
  • Active voice: The size of an opening controls the rate of evaporation.

The passive voice slightly emphasizes “the rate of evaporation,” while the active choice emphasizes “the size of an opening.” Simple. So why all the fuss? Because the habit of overusing passive constructions rules too many writers, who habitually produce grammatically tangled sentences such as this one:

  • Groundwater flow is influenced by zones of fracture concentration, as can be recognized by the two model simulations (see Figures 1 and 2), by which one can see . . .

In general, use active voice most often in technical writing as opposed to passive voice. Part of the skill of using active verbs lies in choosing the verbs that precisely describe the action you want to convey. Whenever possible, avoid bland verbs and use more precise, descriptive verbs. Passive voice sentences can become a burden for the reader, and probably for the writer too. Passive voice can smother potential verbs and require a lot of prepositions, or “of” phrases. See how much more easily you can read the revised version below:

  • Two model simulations (Figures 1 and 2) illustrate how zones of fracture concentration influence groundwater flow. These simulations show . . .

To revise the above, all I did was look for the two buried things (simulations and zones) in the original version that could actually do something, and I made the sentence clearly about these two nouns by placing them in front of active verbs. This is the general principle to follow as you compose in the active voice: Place concrete nouns that can perform work in front of active verbs representing the nature of the work done.

But suppose you are writing a report where you may not use “I,” or you are writing about a sentence subject that can not actually do anything. What to do when the passive voice is the best, most natural choice?

The answer lies in writing direct sentences—in passive voice—that have simple subjects and verbs. Compare the two sentences below:

  • Photomicrographs were taken to facilitate easy comparison of the samples.
  • Easy comparison of the samples was facilitated by the taking of photomicrographs.

Both sentences are written in the passive voice, but for most ears the first sentence is more direct and understandable, and therefore preferable. Depending on the context, it does a clearer job of telling us what was done and why it was done. Especially if this sentence appears in the “Experimental” section of a report (and thus readers already know that the authors of the report took the photomicrographs), the first sentence neatly represents what the authors actually did—took photomicrographs, and why they did it—to facilitate easy comparison.

Note that using passive voice does not have to create ambiguity or complicate wording. When you use the passive voice, seek economy and clarity. Avoid such empty and ambiguous phrases as “it might be thought that” (try “perhaps”) or “it is to be supposed that” (try “presumably”) or “the theory that is held by the writer of this report at the present time of this writing” (try “It is theorized that”) or “one should think of” (try dropping it completely). At times the passive seems unavoidable, but the passive can often be switched to the active with some simple rewording, and both the active and the passive voice can be direct, efficient, and clear in context, as you can see from the examples below. In your writing, you must strive to use both of them well.

Passive vs. Active Voice
Passive voice Active voice
Saccharin is now permitted as an additive in food. The FDA now permits saccharin as an additive in food.
This report is divided into three main sections. I have divided this report into three main sections.
Windmills are classified as either lift or drag types. Engineers classify windmills as either lift or drag types.
The valves used in engine start are controlled by a computer. A computer usually controls the valves used in an engine start.
The remains of Troy were destroyed by later builders on the site. Later builders on the site of Troy destroyed the remains of citadel.
Some restaurant locations can be leased. You can lease some restaurant locations.

When to Use Active Voice

Use active voice in the following circumstances:

In the topic sentences and the opening sentences of paragraphs, so the topic for the paragraph is clearly announced:

  • Crustal rocks contain an interesting historical record. First, they reveal . . .
  • Batteries, inductors, and capacitors provide electrical energy storage. In batteries, high internal resistance allows for . . .

When referring to another author’s work or introducing a figure or table, put the author’s name or the figure or table right into the subject of the sentence, then follow it with an active and literally correct verb:

  • Feldman explains how the relative brightness of objects depends on the viewer’s angle of observation.
  • Figure 2 illustrates how fractal geometry can be used to create realistic landscapes.

 

Sample active voice paragraph

The following excerpt from a meteorology paper demonstrates the effectiveness and efficiency of active voice. The paragraph explains the complex concept of vorticity through an analysis of the seemingly ordinary phenomenon of smoke rings. Note the consistent use of simple exact subjects followed by active descriptive verbs.

Figure 4 depicts a smoke ring in which the layers of a toroidal vortex ring are visible. As the picture shows, the smoke ring moves away from its source and trails smoke from its center. The trail of smoke behind the moving smoke ring indicates that the same viscous stress that caused the smoke ring to form also causes its eventual destruction. As the smoke ring continues to move (Figure 5), the outside boundary of the ring rotates toward the same direction as the relative motion of the surrounding air. The inside boundary rotates opposite in direction, and thus the change in relative velocity with distance across the boundary produces drag.

When to Use Passive Voice

Use passive voice in the following circumstances:

Throughout the “Experimental” section of a scientific report, or anywhere that you must summarize your own or another author’s experimental procedure or findings, but the actual inclusion of names would be awkward, distracting, or unconventional:

  • Initially, a fractured steel specimen was plated with electroless nickel and secured in an epoxy mount by vacuum impregnation.
  • The findings of the November 1997 report to NASA were based on DMTA, DSC, and FTIR test results.

In formal abstracts (condensed summaries) that introduce papers:

  • Sensitivity experiments are reviewed to investigate the influence of Pacific sea surface temperature anomalies on blocking in the Northern Hemisphere.

When it makes sense to emphasize the receiver of the action rather than the doer:

  • The samples should be monitored regularly and should be dried carefully once they are cool.
  • Winter wheat is planted in the autumn and ripens in the following spring or summer.

When emphasis or variety demands it, or when the flow of your paragraph suggests that a passive construction is the most clear choice:

  • One facet of multiple phase transformation can be seen through an examination of the gas gathering process. This process . . .

try it

Revise the following paragraph re-phrasing passive into active voice, using active, descriptive verbs. Also try to condense the paragraph by revising some of the “to be” verbs and “of” constructions, which you can eliminate by moving to active voice. And, if you find an appropriate topic sentence, place it at the start of the paragraph.

Energy Drinks are able to be consumed in many varied and different ways by people all over the world. Moreover, drinking these energy drinks is able to provide people in today’s society with the helpful benefits of increased awareness and energy. Besides, even though there are enhancements that may be present from drinking an energy drink, the negative side effects are posing more of a threat to a person than the energy boost that is able to be achieved. In a survey that was taken in the United States at an American university, it was reported that fifty one percent of participants were consuming greater than three energy drinks each month in the semester [1]. Looking at this statistic, it can be seen that a majority of students in university are drinking energy a large amount of drinks on a very regular basis. Which can be the cause of some health problems experienced by students. In the same study, it was also shown that energy drinks are capable of helping to increase energy and athletic endurance; for those who drank it. Despite the fact that there are some benefits to be had from drinking energy drinks, there is the problem of the negative side affects that are caused by the drinking of these energy drinks. However, the side affects that were commonly reported in the study are: headaches, and “energy crashes” (Smith 5). Being a potentially more severe problem than the minor problems of headaches and “crashes;” there is definitely the possibility of people which are becoming addicted to caffeine.

Sentence Variety

Experienced writers incorporate sentence variety into their writing by varying sentence style and structure. Using a mixture of different sentence structures reduces repetition and adds emphasis to important points in the text.

Add phrases in different places within sentences – sometimes at the beginning, sometimes in the middle, and sometimes at the end, making sure that the phrases are placed to create the meaning you intend. For example:

  • Original sentences: The managing director is visiting the company next week. He lives in Seattle.
  • Revised sentence: The managing director, who lives in Seattle, is visiting the company next week.

Combine short sentences sporadically throughout the paragraph or document. For example:

  • Original sentences: Prewriting is a vital stage of the writing process. Prewriting helps you organize your ideas. Types of prewriting include outlining, brainstorming, and idea mapping.
  • Revised sentence: Prewriting is a vital writing process stage that includes outlining, brainstorming, and idea mapping; it helps you organize your ideas.

 

sample paragraphs showing sentence variety

Read the following two versions of an extract from an election campaign. The first uses short, simple sentences of a similar length and style, which creates a somewhat “choppy,” unsophisticated paragraph that may not grab your attention.

The second version varies the sentence structures. The writer combines the choppy sentences at the beginning into one longer sentence, which adds rhythm and interest to the paragraph, and also introduces a short rhetorical question among the longer sentences in the paragraph to keep your attention.

Version 1

During my time in office I have achieved several goals. I have helped increase funding for local schools. I have reduced crime rates in the neighborhood. I have encouraged young people to get involved in their community. My competitor argues that she is the better choice in the upcoming election. I argue that it is ridiculous to fix something that isn’t broken. If you reelect me this year, I promise to continue to serve this community.

Version 2

During my time in office, I have helped increase funding for local schools, reduced crime rates in the neighborhood, and encouraged young people to get involved in their community. Why fix what isn’t broken? If you reelect me this year, I will continue to achieve great things for this community. Don’t take a chance on an unknown contender; vote for the proven success.