Answer:
the error is in the incorrect usage of "quick."
Explanation:
In the sample sentence, the word quick is in the verb form when it should have the -ly ending to denote that it is an adverb. That is to say, since it is describing the verb "works" it should be the adverb "quickly" instead.
The answer is gait.
Definition of gait : a person's manner of walking
Answer:
The cat hid his mouse toy under the bed would be correct. In this sentence the comma is not needed.