Structure

A simple sentence consists of a single independent clause, which itself contains a subject (noun) part, a predicate (verb) part, and an appropriate mark of punctuation.

A compound sentence consists of two or more independent clauses. These clauses are connected either with a semi-colon or with a comma and coordinating conjunction such as for, and, nor, but, or, yet, so

A complex sentence consists of one independent clause connected to one or more dependent clauses. A dependent clause, like an independent clause, contains a subject and a predicate; however, the dependent clause is preceded by a subordinating element, such as after, because, during, even though, however, if, since, though, unless, and while.

A compound-complex sentence consists of two (or more) independent clauses and one (or more) dependent clauses:

Function

A declarative sentence is used to indicate a statement. Most sentences used in communication are declarative:

He wanted to leave, but he couldn't go.

An interrogative sentence is used to indicate a question. An interrogative sentence is noted by its ending punctuation, a question mark:

Did he really want to leave?

An exclamatory sentence is used to indicate an exclamation, or an expression of thought mixed with strong emotion. Like an interrogative sentence, an exclamatory sentence is noted by its ending punctuation, an exclamation point:

He wanted to leave!

An imperative sentence is used to indicate a request or a command. An imperative sentence will always use the second-person "you" form in the subject and the predicate:

Accept the first bid, not the second one.

Prepositional phrases can be used as adverbs or adjectives:

In a flash, she realized that the tofu had been underneath her chair all along.

Infinitive phrases consist of an infinitive (to dance, to fly, to circumnavigate, etc.) plus an object. They are usually used as nouns, but they can also be used as adjectives or as adverbs.

To see him suffer is my dearest wish.

Participial phrases consist of a participle plus an object. They are used as adjectives.

The creature suffering in the dungeon was once beautiful.

Gerund phrases begin with a gerund (an -ing word which looks exactly like a present participle, but which is used as a noun.) A gerund phrase can be used in any way a noun can:

As subject: Playing canasta has been her downfall.

As direct object: He loves embarrassing his relations.

Independent clause can stand alone

A dependent clause has a subject and a verb, and looks exactly like an independent clause except for one small thing: it is introduced by either a relative pronoun or a subordinating conjunction, which makes the clause grammatically "dependent" on the rest of the sentence.

Subject + Verb I swim. Joe swims. They swam.

Subject + Verb + Object I drive a car. Joe plays the guitar. They ate dinner.

Subject + Verb + Complement I am busy. Joe became a doctor. They look sick.

Subject + Verb + Indirect Object + Direct Object I gave her a gift. She teaches us English.

Subject + Verb + Object + Complement I left the door open. We elected him president. They named her Jane.

Simple Present Once a week, Tom cleans the house. Once a week, the house is cleaned by Tom.

Simple Past Sam repaired the car. The car was repaired by Sam.

Simple FutureSomeone will finish the work by 5:00 PM.The work will be finished by 5:00 PM.

Present Perfect Many tourists have visited that castle.That castle has been visited by many tourists.

Past Perfect George had repaired many cars before he received his mechanic's license.Many cars had been repaired by George before he received his mechanic's license.

Future PerfectThey will have completed the project before the deadline.The project will have been completed before the deadline.

Present Continuous Right now, Sarah is writing the letter.Right now, the letter is being written by Sarah.

Past Continuous The salesman was helping the customer when the thief came into the store.The customer was being helped by the salesman when the thief came into the store.

Future ContinuousAt 8:00 PM tonight, John will be washing the dishes.At 8:00 PM tonight, the dishes will be being washed by John.