题目

The family has been in American_.
a.for a last year b.since last year
为何选 a
I _ for mushrooms but I haven't found any.
a.have been looking b.have looked
为何选 a,b 错在哪
It was so dark outside that he_.
a.didn't dare to go out to fetch water
b.dare not to fetch water
为何选 a

提问时间：2020-10-01

答案

从语法角度来讲这几个选项都没有错,只是语义不同,要根据上下文意思来理解.1.for a last year 意思是已经在美国一整年了,强调这一整年都在,last 表示一个持续的概念.since last year 意思是自从去年就在美国了,强调从...