問題補(bǔ)充：
單選題
He devoted most of his time to researching into space, believing his hard work would ______ sooner or later.A.pay backB.pay forC.pay offD.pay up
網(wǎng)友答案：
熱心網(wǎng)友 1樓
C解析考查短語辨析，pay back償還，pay for為了什么付款，pay off還清，得到回報(bào)，pay up 付清，句意：他把他的大部分時(shí)間獻(xiàn)身于研究太空，相信他的努力工作遲早會得到回報(bào)的。故選C。
