In English writing, we value variations in sentence structure the way we value rhythm  and cadences in speech. If every sentence consists of subject, verb, predicate, in that order, the writing very quickly becomes  monotonous. So we might have a long sentence followed by a short, punchy one, or a simple declarative sentence before one with a couple of dependent clauses. From Lincoln’s second inaugural address:

Both parties deprecated war; but one of them would make war rather than let the nation survive; and the other would accept war rather than let it perish. And the war came. 

Lincoln’s is a compound sentence — one whose clauses are of equal weight, joined by conjunctions — and that’s one way of varying sentence structure. Another is to write complex sentences — those with dependent clauses. Complex sentences can make your writing smooth and sophisticated.

Here’s a make-over from student work:

Saalim Choedhury is a media consultant based in London. Mirror is the paper he worked for.

Two short, choppy sentences: subject verb, predicate nominative. Two possible fixes:

Saalim Choedhury is a media consultant based in London who worked for Mirror.  

Even tighter using an appositive:

Saalim Choedhury, a media consultant based in London, worked for Mirror.

Which you choose may depend on what you want to emphasize. What’s more important — ID’ing him (the first) or the fact that he worked for Mirror (the second)?

Some of your 5W words can come in handy in constructing complex sentences: who (or whose), when, where. Which or that clauses add descriptive information as well as texture. You use time words — before, after, when, while, since — to introduce clauses in everyday conversation: I’ll have lunch after I finish this story.  So why not in your copy?

From another student:

When Anna Papakonatsantinou, a high school graduate from Mytilene, Greece, told her parents that she wouldn’t enter university and would instead move to the countryside to grow grapes, they felt they had breached their lifelong promise. 

OK, it’s a long sentence. The when clause contains a second dependent clause, the one starting with that. So does the main clause: they felt (that) they had breached their lifelong promise. One sentence, four clauses — yet the meaning is perfectly clear.

Here’s a writing sample that would benefit from being reworked into a complex sentence:

Arizona’s locals noticed another out-of-state migration – a seasonal one from colder places. Navarro referred to them as  “snowbirds.”

Instead, how about:

Arizona’s locals noticed another out-of-state migration – a seasonal one, of people from colder places, whom Navarro called  “snowbirds.”

Because complex sentences can be so complex, it’s crucial that they be properly punctuated. From one of my correspondents — a journalism professor, no less:

After that, I leave for Miami where I hope to live the next few years on March 20.

That sentence cries out for commas: After that, I leave for Miami, where I hope to live the next few years, on March 20. Otherwise, it sounds as if the writer expects to be living in some sort of time warp. (Remember that commas generally travel in pairs. If you have a dependent clause in the middle of the sentences, it needs them at beginning and end.)

Complex sentences tend to run long, so be careful that yours isn’t too complex. From a recent theater review in The New York Times:

Unless you slept through the late 1980s and the 1990s, folks, you probably know by now that I refer to Ann Richards, the onetime governor of Texas, whose life and career are being given a ticker tape parade on the stage of the Vivian Beaumont Theater, where the new Broadway show “Ann,” written by and starring Holland Taylor, opened on Thursday night. 

That’s a mouthful, or maybe a brainful: 62 words. I count  four dependent clauses (the ones with unless, that, whose and when), an appositive (the onetime governor of Texas) and a couple of participles used as adjectives (written and starring). Most important, the sentence just goes on too darn long. Here’s how it might have been edited had the copy desk not been overwhelmed on deadline:

Unless you slept through the late 1980s and the 1990s, folks, you probably know by now that I refer to Ann Richards, the onetime governor of Texas. Her life and career are being given a ticker tape parade on the stage of the Vivian Beaumont Theater, where the new Broadway show “Ann,” written by and starring Holland Taylor, opened on Thursday night.

In this case, only a period and a new pronoun were needed to give the reader a break. An easy test: read the sentence aloud. If you find yourself gasping for air before you reach the end, your reader probably will, too.