Question

There is someone knocking at the door. It must be the computer repairman.I（ C ）him to come t

There is someone knocking at the door.
It must be the computer repairman.I（ C ）him to come to fix my computer.
A.call B.have called C.called D.will call
AD选项我已排除 BD选项是现在完成时和一般过去时的区分 一直弄不懂 求帮助掌握现在完成时和一般过去时在没有时间标志词时怎么区分

Answer 1

There is someone knocking at the door. It must be the computer repairman.I（ C ）him to come to fix my computer.
有人在敲门，一定是电脑维修工，我打电话叫他来修理我的电脑的。
根据题干There is someone knocking at the door. It must be the computer repairman．有人在敲门，一定是电脑维修工。可知修理工现在已经来了，所以可以推断：电话是过去打的，应该用一般过去时态。一般过去时态的构成：主语+谓语动词的过去式。所以答案是：called，故选：C。
本题主要考查动词时态，判断动词的时态，要通过所给的时间状语或上下文等，去判断动词的时态。本题主要考查一般过去时态。

Answer 2

答案B， have called . 

A:There is someone knocking at the door. 

B： It must be the computer repairman.I have called him to come.

这是一个表示猜测的情景。 B这个人对自己的推断用了must be 的语气，他之所以做出这么肯定的推测，是因为他觉得之前自己打电话叫了修理员的。 尽管打电话叫修理员这件事发生在过去，但是对B这个人而言他觉得很大程度上影响了现在对门口是谁的推测。 故，用现在完成时。 类似的情景还有：

A: Is the man under the tree our headmaster?

B: No, it can't be him.  He has gone to attend the meeting. 

其中一个用法： 现在完成时表示一个过去发生的动作在过去已经完成，并且这个动作对现在仍有影响或结果，同时说话者强调的或感兴趣的就是这个影响或结果，如汉语说“他已离开这个城市了”，其中的“离开”肯定发生了，它对现在的影响或结果就是“他现在已不在这个城市了”He has gone to Beijing. (He has left and gone to Beijing. He is not here.)

Answer 3

There is someone knocking at the door. It must be the computer repairman.I（ C ）him to come t
有人在敲门。它必须是计算机修理工。我（C）他来T