Analytical Writing for Science and Technology
Copyright © 1996 by T. M. Georges.

Lesson 13

The Dependent Clause -- A Natural Way to Write Analytically


In this Lesson:

In this lesson, you'll learn how to use a powerful tool for analyzing the details you have to write about. It's called the dependent clause. Don't worry about the formidable name -- it's just the same way you use to describe relations between ideas in ordinary conversation.


First, let's make sure you know how to recognize a dependent clause when you see one. Here are some examples of sentences with dependent clauses in them. The dependent clauses are in boldface.

The project was not completed on time, because the machine parts were stolen.

If at first you don't succeed, try something else.

A helium nucleus has two protons, whereas hydrogen has only one.

Although Klingon battle cruisers are not very maneuverable, they can make themselves invisible.

Where were you when President Kennedy was assassinated?

Energy supplies will dwindle, unless we conserve.

Notice how each dependent clause can't stand by itself, even though it has a subject and a verb of its own. Instead, in some way it amplifies or qualifies the statement in the main part of each sentence. The first boldface word in each case is the key. It goes by the horrible name of subordinating conjunction, but don't worry about that.

Dependent clauses can also begin with relative pronouns, as in these examples:

Where are the parts that I ordered?

The uranium nucleus, which contains 92 protons, is unstable.

Most people don't know who their senators are.

What the aerospace industry needs now is more friends in Congress.


You don't need to worry about the grammatical terminology -- you just need to understand how dependent clauses qualify, limit, expand and explain detail -- how they highlight the important and suppress the incidental. And that's what Analytical Writing is all about.

All you really have to remember are these surprisingly short tables of words for linking ideas and showing how they are related:



These are the good guys! If you start using these words to introduce dependent clauses, I guarantee that your writing will improve. Copy this list and keep it in front of you during your writing assignments. Make a conscious effort to use words from this list to relate and amplify your ideas.


In the following examples, underline the dependent clauses and circle the subordinating conjunctions. If you can, write down also the function of each clause in the sentence (for example, does it function like a noun, and adjective or an adverb, and is it the subject, object or a modifier in the sentence?) If you can't, it doesn't matter.

I want you to remember how you tuned the transmitter.

The reaction took longer than he expected.

If I have time, I will buy the dynamite.

We found the parts that you ordered, but they were radioactive.

Chamberlain defied the pessimists who predicted that he would fail.

We searched the spot where I lost the bagels.

Employees who work hard will receive a gold star.

Michelson said that he knew why the experiment burst into flames.

That the cast-iron airplane would fly was doubtful.


There are many ways to combine related ideas. The best ways are the ones that precisely define relations among ideas, by explaining, contrasting, limiting and expanding. Consider the string of ideas in these isolated sentences:

Eunice set fire to the cat.
The cat jumped into the pool.
The cat could not swim.
Rodney rescued the cat.

You could combine the ideas, linking them with semicolons:

Eunice set fire to the cat; the cat jumped into the pool; the cat could not swim; Rodney rescued the cat.

Or you could combine them as independent clauses, using only and:

Eunice set fire to the cat, and the cat jumped into the pool, and the cat could not swim, and Rodney rescued the cat.

Using but and so clarifies the relations a bit more:

Eunice set fire to the cat, and he jumped into the pool, but the cat could not swim, so Rodney rescued him.

Finally, dependent clauses make things even more vivid:

After Eunice set fire to the cat, he jumped into the pool, but because he couldn't swim, Rodney rescued him.

Do you see the difference between simply listing the four ideas and linking them together with words that define precisely how they are related?

Practice forming dependent clauses by combining each of the following sets of isolated ideas into one sentence. Use the subordinating conjunctions from the above list (or make up ones of your own) that best describe the probable relations among the ideas.

The airplane landed. We got off. We discovered we were not in Pittsburgh. We were in Havana.

The program was written in FORTRAN. It is longer than a machine-language version. It can run on many different computers.

Computer maintenance costs kept increasing. Georgette complained about peanut butter on the diskettes. Mr. Figby banned food from the computer room.

Doppler radars measure radial velocities. A conventional radar cannot. Doppler radars are useful for remote sensing.

The goat ate Bertha's leotards. Bertha couldn't perform in the comapany ballet. Bertha went to the movies instead.

The operating manual contains some simple maintenance procedures. We urge you to call a service man for repairs. Unauthorized service may void your warranty.

Another useful linking word is but. Technically, it's a coordinating conjunction, used to join independent clauses. Use it, along with your other tools, to contrast ideas, as in the following exercises:

Word processors permit efficient manuscript typing. They make revisions a lot easier. They require an investment of several thousand dollars. The operators must be trained for a week.

Janice read the instruction manual very carefully. She hit the ! key. The terminal exploded.

CAUTION: I am not generally urging you to patch several short sentences into one long one. You will need to decide in each case whether doing so will help you define more clearly the relations among ideas.

Find a paragraph or two that you have written recently and underline all the dependent clauses. If you don't find very many, you can be sure that your sentences aren't informing as well as they could. Try rewriting your paragraphs so that at least half the sentences contain dependent clauses.


Before we go on to some more exercises to give you practice using dependent clauses, let's look at the usual, less informative alternative to the dependent clause. It's called the prepositional phrase. Here are some examples:


You learned in grammar school about simple, compound and complex sentences. It's too bad that sentences with dependent clauses in them got the label complex. Most people are frightened by the word complex, because it usually means complicated. Why use a "complex" (meaning complicated) sentence when you can use a simple one? Well, here's another fine mess grammatical terminology has gotten us into!

  • in progress
  • on the floor
  • beside the garage
  • between the cities
  • of data-processing equipment
  • to a Martian
  • by walking on hot coals

The first word in each phrase is the preposition. Notice that these phrases have no verbs in them. Clauses always do. (In the last example, walking is formally a noun.)

One way to tell that ideas are being merely listed or cataloged is to notice how many prepositional phrases you have. When there are too many of them, you know that all ideas are being treated as grammatically equal. There's no discrimination, no emphasis among qualifying details. When you don't supply that discrimination and emphasis, your readers have to do that themselves. And that's just what you want to avoid.

So here's a simple rule for improving the way you present details:


Here are some sentences that put their details entirely in prepositional phrases. Use your yellow highlighter to mark all the prepositional phrases. As a check, I note the number of phrases after each sentence.

Then rewrite each sentence to give the same information, but using no prepositional phrases:

In their specifications for engine parts, titanium is often requested by engineers because of its resistance to the effects of high temperatures. (6)

Uncertainties in the market for American cars is of concern to leaders of the industry, due to the increases in the costs of labor and raw materials. (8)

In the design of components for warp drives for starships, increasing attention is being given to the employment of dilithium crystals because of their high power output in relation to their weight. (9)

The emphasis of this research is on new ways of measuring currents in the ocean with radar for the purpose of studying their effects on climate.(8)

Take a paragraph or two from your own writing and mark all the prepositional phrases in yellow. Try rewriting your paragraphs, removing as many of the prepositional phrases as you can.


Scientific and technical writing are nortorious for cataloging details by stringing bunches of adjectives in front of nouns. These are sometimes called noun strings. Here are some examples I extracted from actual technical writing:

development flight instrumentation recorders

agency management planning system enhancements

inferior product labeling requirements

multichannel complex maximum-entropy (autoregressive) spectral analysis

digital 8-pole variable-bandwidth lowpass filter

surface water quality protection procedures development

canister/missile launch support stand (TSE4508) interface design

They don't make any more sense when you see them in context, either. Here are a few sentences that cause most readers to do a double-take. Underline the piled-up adjectives:

The QX-7 is the first extra-long range (800-1000 miles), low-silhouette pilotless target aircraft to be built entirely of fiberglass.

The top-level fire-control-related generic requirements are stated explicitly in the proposal.

The detail media measurements are particularly useful in the continuous refinement of one and two-dimensional laser peformance calculations.

It was necessary to run the transient counterflow program to obtain the average temperature history of a mass averaged nozzle and the deuterium coolant exit temperature history.

The closed-cavity power data base was used to establish the gain generator run conditions at the various power points specified.

In these examples, technical adjectives are so crammed together ahead of nouns that it's not even clear what they mean.

What can you do about strings of technical adjectives? If you're tempted to translate them into strings of prepositional phrases, don't! That's sometimes an improvement, but as you just learned, prepositional phrases are catalogers of ideas, too.

The first example above can be rewritten using a dependent clause:

The QX-7, which is the first pilotless aircraft to be built entirely of fiberglass, combines a range between 800 and 1000 miles with a low radar silhouette.
Go ahead and rewrite the other four sentences, using dependent clauses to clarify the relations among ideas.

Now, take a paragraph or two of your own writing and underline any strings of technical adjectives. Rewrite those sentences using more analytical constructions.


When you use dependent clauses (that is, complex sentences), you write in the most natural, yet informative style possible. You bring the important ideas into the spotlight and analyze their interrelations. Listing ideas in strings of adjectives or prepositional phrases, on the other hand, just catalogs them.

The next four lessons are short ones. They'll show you four simple steps for making your sentences hang together in coherent paragraphs. The same analytical principles apply to these larger writing units as to words and sentences.

-- End of Lesson 13 --

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