A paragraph can only be as clear as the sentences inside it. Grammar handbooks list hundreds of rules, but a few principles do most of the work of making sentences easy to read. They rest on one observation: readers take in a sentence in order, word by word, and build expectations as they go. Sentences that meet those expectations feel clear. Sentences that defy them feel hard, even when every word is correct.

Characters and actions

Readers understand a sentence most easily when it tells a small story about someone doing something. The American writing teacher Joseph Williams built much of his influential style textbook on this idea, which comes down to a simple piece of advice: make the main characters the subjects of your sentences, and put their actions in verbs. Compare "There was a failure on the part of the board to provide oversight of the budget" with "The board failed to oversee the budget." The second names the character (the board) as its subject and puts the action in its verbs. It is shorter, and it is clearer about who did what.

Keep the subject and its verb close together, too. When a long phrase separates them, the reader has to hold the subject in memory while waiting to learn what it did. "The report, which had been drafted over six months by a committee of nine people drawn from three departments, concluded that..." makes the reader wait. Moving the description elsewhere lets the sentence reach its point.

Active and passive voice

In the active voice the subject performs the action: "The inspector closed the restaurant." In the passive voice the subject receives it: "The restaurant was closed by the inspector," or simply "The restaurant was closed." Notice what happens to the actor. In a passive sentence the actor moves to the end or disappears entirely. That can be a problem. "Mistakes were made" admits an error without saying who made it, which is why the phrase has such a long history in official apologies.

The passive is not wrong, though, and writers who ban it outright often make their prose worse. The passive is a reasonable choice when the actor is unknown or unimportant ("The bridge was completed in 1883"), or when it lets a sentence keep its focus on the topic the paragraph is about. The question is never "Is this passive?" but "Does the reader need to know who acted, and is that clear?"

Old information before new

Each sentence in a passage should connect to the one before it. The simplest way is the old-to-new principle: begin a sentence with information the reader already has, and end with what is new. "Bees carry pollen from flower to flower. This pollen fertilizes the plants, which can then produce seeds and fruit." The second sentence starts with "this pollen," which the reader has just met, and ends with the new idea. Flip the order and the passage feels jumpy, even though each sentence alone is fine.

The principle has a partner. In 1990 George Gopen and Judith Swan argued, in an article on scientific writing, that readers naturally give the most weight to whatever comes at the close of a sentence. The end of a sentence is its stress position, the place where emphasis falls. Put the word or idea you most want remembered there, not a weak trailing phrase like "in many cases" or "at this point in time."

Length, rhythm and parallelism

Many style guides suggest that sentences in public documents average somewhere around 15 to 20 words. Treat this as a rough guide, not a law. A long sentence can be perfectly clear if its structure is simple, and a page of nothing but short sentences sounds choppy. What matters most is variety: mix sentence lengths so the rhythm does not become monotonous, and save the shortest sentences for points that deserve weight.

When a sentence lists several items, put them in the same grammatical form. "She likes hiking, to swim and riding bikes" stumbles; "She likes hiking, swimming and cycling" flows. Faulty parallelism means listing items in different grammatical forms, and readers feel it as a bump even if they cannot name it. Watch also for the dangling modifier, an opening phrase that does not attach to the word it is meant to describe: "Walking to the station, the rain soaked my coat" says that the rain was walking.

Worked example: a sentence from a city report

A draft city report contains this sentence: "Implementation of the new recycling program by the sanitation department, after a period of consultation with residents and businesses that lasted several months, resulted in a reduction of landfill waste."

First, find the character and the actions. The character is the sanitation department; the actions are consulting, launching and reducing. Second, bring the subject close to its verb. Third, end each sentence on its newest and most important information. The revision: "After consulting residents and businesses for several months, the sanitation department launched a new recycling program. Within a year, the city was sending a fifth less waste to the landfill."

The revision splits one tangled sentence into two clear ones, names who acted and puts the payoff, the drop in waste, in the stress position. One caution: the "fifth" is a figure the writer would need to confirm from the city's data before publishing. A clearer sentence still has to be a true one.