Which sentence contains an inappropriate shift in tense? a. lauren laughed out loud after she listens to joke. b. as the children play, jonah is happy to relax with a book. c. sometimes the dog runs around and chases its own tail.

quite an interesting way to teach topic sentences, because the answer to this question is the best definition of a topic sentence that one can present, it is as if answering the questions taught you how to do it, this is some real teaching, it is terribly well-done.

the topic sentence in this paragraph is:

topic sentences writers stay on track and keep a paragraph from becoming an aimless collection of sentences about an idea.

which incidentally tells you what a topic sentence should be.