现在完成时的用法和题目

顾名思义,就是现在已经完成了的动作：His homework all have been finished=He has finished his whole homework.
既然是现在才完成,则一定是从过去就开始进行的,因此也常用来表示过去就已经完成的事,但与现在存在某种关系时：He has ever lived in China.(注意他现在已经不在中国住了)；但是注意这种用法,即该动作从过去开始,到现在可能仍在继续：He has worked as a teacher for a long time.可能现在已跳槽了,也可能还在当老师.这也是与过去一般时的本质区别哦.
最后,注意 be 在此时态下的不同用法,可为实义动词即 have been ,也可为表被动的助动词即 Have been done ,要小心区分啥.It's known he has been punished for something.It's known he has been well there,