SENTENCES

Can a sentence that expresses a command be written without stating the grammatical subject?

Yes. Sentences which give directions or commands are called "imperative" sentences. They usually begin with a verb and end with a period or exclamation point:

Take out the trash.

Adjust the left control for optimum reception.

Do not change the factory settings!

What is the difference between a compound and complex sentence?

A compound sentence is a combination of two or more simple sentences. (A simple sentence expresses one complete thought.) These simple sentences are linked by a coordinating conjunction (and, but, or, for, yet, not, so), a semicolon, or a semicolon and a conjunctive adverb:

The weather was pleasant, but the wind kept us from sailing.

The costs are much too high; we'll have to look elsewhere.

The acoustics were poor; however, we could hear their voices. 

A complex sentence is the union of a simple sentence and a dependent or subordinate clause. (A dependent or subordinate clause cannot stand alone as a simple sentence.) The dependent or subordinate clause can appear before, in the middle of, or after the simple sentence:

Although the content was brief, the message was convincing.

Indirect people, who move at a slower pace, are very cautious.

Adaptability is difficult because we tend to be very egocentric.

How long should an average sentence be in business and technical writing?

A combination of long and short sentences whose average length within a document is about 20 words will foster readability. Long sentences are useful for presenting involved concepts. Short sentences are more emphatic; they can state clear, crisp thoughts.

What are other ways to enhance sentence readability?

Readability is improved by maintaining a fairly uncomplicated sentence structure (keeping the subject and verb close together, keeping modifiers close to words that they modify, using appropriate transitions). Direct (active) sentences are preferred.

Employing a variety of sentence types (simple, complex, and compound) helps to sustain reader interest and enhance readability.