We need to _____ the shoes before we decide to buy them.
辨析动词短语。
四个选项的含义分别是：turn on打开；look for寻找；try on试穿；wait for等待。根据语境可知，在我们决定买鞋之前，我们需要“试穿”一下，故答案为C。
—Do you think Jim will pass the exam?
—Sure. He usually _______ a lot of time working on it.
本题考查spend的用法。
答语中提到了“他通常花很多时间去准备考试”，主语是He，再根据其后的working on it可知所缺的词是spends，该句的结构是“sb. spend(s) some time doing sth.”，故答案为A。