Main clauses

- A main clause is one that could stand alone as a sentence. For example,

He took the lift up to the 86th floor.
A gust of wind caught him.

- We can use and, or, but, and so to join two or more main clauses. For example,

He took the lift up to the 86th floor, and he jumped.
He could go through with it, or he could go back down again.
He jumped from the 86th floor, but he survived.
It was a live show, so the host invited him on.

- Two main clauses linked together like this are called 'co-ordinate clauses'.
When the subject of the two clauses is the same, we can often leave it out, especially after and and or. For example,
He took the lift up to the 86th floor and jumped.

- We can also leave out the auxiliary verb to avoid repeating it. For example,
He could go through with it or go back down again.
We can link more than two clauses. Usually and comes only before the last one. For example,
He took the lift up to the 86th floor, found a convenient window and jumped.

Note:

-We can begin a sentence with and, or, but. or so to link to the previous sentence. For example,

A gust of wind caught him as he felt and blew him into the studios of NBC Television on the 83rd floor. And it happened that there was a live show going out at the time.

-At one time some people believed that it was incorrect to begin a sentence with and, or, but, or so. This attitude is now less common, and you will often see such sentences.