What's wrong with this is the clowns was ready to go on the field trip to the new zoo

The sentence is using the word "was" instead of the word "were". Using "were" is appropriate for talking about the past tense for plural things. Simply change the words. Hope this helped :))

hi u can delete this

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.