题目

but no one has been able to prove that fish is any better for the brain than many other kinds of food
has been able to prove是现在完成进行时?

提问时间：2021-04-01

答案

不是的,就是现在完成时,没有表示进行的部分啊,have done 是现在完成时嘛,只不过这里的done是be + adj.的形式而已