A complete sentence has a subject and predicate, and it can be composed of one or more clauses.

A subject + predicate + ( a group of words) can form a sentence.

Examples:

“I grabbed the pen”

“You ate fish.”

More complex sentences can be made by combining independent and dependent clauses or phrases through the use of conjunctions.

I went to the park and I started running

“I went to the park” and “I started running” are independent clauses combined with the conjunction “and”