I think the best thing you should do is

题目

I think the best thing you should do is
I think the best thing you should do is ____ another job.
A.looking for B.looked for C.look for D.about to look for

答案

C.look for
the best thing you should do 这个主语部分有do,从you should do"你该做的“ 来看,指的是说话以后该怎么样去做,此时系表结构中,作表语的一般用不定式to do sth ,to 可以省略,也可以不省
再如：
The first thing for you to do is【 find out】 when the train leaves