(Please download the file) Review: The main idea must always be expressed as a sentence. It must also contain a topic and must make complete sense by itself. Here are some examples to illustrate the difference between a topic and a main idea sentence:

 Reality TV shows. No. It's a phrase, so it could be a topic. It's not a sentence, however, so it couldn't be a
main idea.
 In recent years, they have become very popular. No. It's a sentence, but it does not make complete sense by
itself. It doesn't tell what "they" refers to. Therefore, it could not be a stated main idea.
 In recent years, reality TV shows have become very popular. Yes. This could be a stated main idea because the sentence makes complete sense by itself.

Directions: Select true for any item that could be used as a main idea sentence. Do not base your decision on whether an item has a period at the end of it. There are periods after all of the items, but not all of them would work as main
idea sentences.

Examples:
True___Online courses are very convenient. Yes, because it is a sentence and makes sense by itself.
Sleep. No, because it is not a sentence.
True___There are differences in male and female brains. Yes, because it is a sentence and makes sense by itself.

Why video games are so popular. No, because it is not a sentence.
He is the top-ranked golfer in the world. No, because although is a complete sentence, it does not make complete sense by itself. We do not know who "he" is.