:They spend two hours on their work.保持句意不变 They spend two hours ____their work.答:in finishing
问题描述:
:They spend two hours on their work.保持句意不变 They spend two hours ____their work.答:in finishing
答
spend 时间 on sth
=spend 时间 (in) doing sth
你这是对的,其实
in可以省略