Question

【题目】It's believed that humans' (祖先)is a kind of monkey.

Answer 1

【答案】ancestor
【解析】句意：人们认为人类的祖先是一种猴子。that humans' ________(祖先)is a kind of monkey. 是一个主语从句，is是单数，所以主语从句的主语也用单数，所以填ancestor。