Compound and Complex Sentences

Compound Sentences A compound sentence has two or more independent clauses that are usually joined by a coordinating conjunction: Henry got a new job, so he has to move. I have a lot of homework, but I am not going to have time to study tonight.

Notice the difference between a simple sentence with a compound verb and a compound sentence with two clauses: SIMPLEMy house guests returned from a long day of shopping and went straight to bed. COMPOUNDMy house guests returned home from a long day of shopping, and we decided to stay at home instead of going out. What is the difference?

Compound sentences with coordinating conjunctions Most compound sentences are formed with a coordinating conjunction: for, and, nor, but, or, yet, so. (FANBOYS) The experiment was deemed successful, yet our results were unsatisfactory. The students were unhappy with their professor, for he often wasted their time in class.

Compound sentence without coordinating conjunctions While most compound sentences are formed with a coordinating conjunction, often good writers decide to eliminate the conjunction and simply add a semicolon: The ambitious student initiated the research; the teacher was pleased by her efforts. The students were unhappy with their professor; he often wasted their time in class.

Complex Sentences A complex sentence has an independent clause with one or more dependent clauses (independent clauses are in italics). Note that introductory dependent clauses must be followed by commas: Since we got to the concert late, we had to make our way to our seats in the dark. We left class early so that we could attend a special lecture.

Comparing Compound and Complex Sentences compound sentences differ from complex sentences in one important way:  In a compound sentence, both clauses have equal importance.  In a complex sentence, the independent clause is more important.

Compare these sentences. COMPOUND  John was tired, but he finished his homework. COMPLEX  Although John was tired, he finished his homework. In the first sentence, the writer is communicating that both clauses are equally important. In the second sentence, the writer is saying that the subordinate clause ("John was tired") is less important than the independent clause ("he finished his homework").

Look at this paragraph with many independent clauses joined with coordinating conjunctions: I went home, but my roommate wasn't there, so I started to cook dinner, but my roommate came in and saw me trying to cook his favorite recipe, but I didn't really know how to make it well, and he got really angry, so I stopped cooking, and he made dinner for us, and then everything was all right.

The independent clauses are underlined, and the coordinating conjunctions are in bold: 1 went home, but my roommate wasn't there, so I started to cook dinner, but my roommate came in and saw me trying to cook his favorite recipe, but I didn't really know how to make it well, and he got really angry, so I stopped cooking, and he made dinner for us, and then everything was all right.

This is better! Notice how it makes use of a variety of sentence structures. When I went home, my roommate wasn't there, so I started to cook dinner. Then, my roommate came in and saw me trying to cook his favorite recipe even though I didn't know how to make it well. I stopped cooking because he got really angry. In the end, he made dinner for us, and everything was all right.