A sentence is made up of a noun and a verb. The parts of the sentence are called the subject which contains the noun and the predicate which contains the verb.
These can be simple: People is a noun; think is a verb. Subject=People, predicate=think. The entire sentence is, "People think."
The parts of the sentence can also be much more complicated.
If you have two sentences and combine them with any of the following words (which are call conjunctions): and, but, or, nor, for, yet, or so, add a comma before the conjunction. Example: Sue bought skates, but Tom stole them. OR, you could use a semicolon instead of one of those connecting words. Example: Sue bought skates; Tom stole them.
Each part that could stand alone is called an independent clause. They are independent because each could be a sentence all by itself. Sue bought skates is an independent clause. So is Tom stole them.
You can connect them with a conjunction. These are: and, but, or, nor, for, yet, and so. Put a comma before the conjunction.
Example: Sue bought skates, but Tom stole them.
You can connect them without a conjunction by using a semicolon.
Example: Sue bought skates; Tom stole them.
Both techniques make two sentences into one longer one.
(Yes, sometimes really short sentences like this don’t need a comma according to some sources, but your editor will thank you if you use them anyway. He or she can decide if the comma adds clarity.)
