as to do 的用法

1、Best to have as little to do with people of his sort as possible.像他这号人，还是少跟他来往好。

2、James was at a loss as to what to do and felt lost.詹姆斯无所适从，惘然若失。

3、You need brains as well as brawn to do this job.这项工作既需要脑力又需要体力。