hasdone是什么时态

　　He has done sterling work on the finance committee.

　　他在财务委员会工作优异。

　　As far as I'm aware , nobody has done anything about it.

　　据我所知，尚无人对此采取任何措施。

　　His equivocal response has done nothing to dampen the speculation.

　　他模棱两可的`回应丝毫没有减弱人们的猜测。