情态动词的时态 Although h

问题描述

Although he can somehow present challenges for me,I don't know if he could have presented the challenge for me to continue on to this season.

could have presented在这里是什么时态？如果换成can have presented呢？

老师答疑

刘老师：

Although he can somehow present challenges for me, I don't know if he could have presented the challenge for me to continue on to this season.

【翻译】虽然他能以某种方式给我带来挑战，但我不知道他是否可能给我一直持续到这个赛季的挑战。

【分析】

1. he can present challenges for me：表示能力。说明他有这个“能力”。

2. he could have presented the challenge for me：表示对过去情况的推测。说明他是否“可能给我带来了挑战”。（指“过去”。即便刚刚发生，也是过去。）

【说明】前句是说：他有这个能力。后句是说：他是否做到了。

3. to continue on to this season：作challenge 的定语，表示同位关系。

【语法知识】could have done 表示“对过去的可能性推测”，could语气较can弱。

该结构表推测时，无肯定式，一般用于否定句和疑问句，也可用于表示“是否”的不确定的whether和if从句。否定句表示“过去不可能发生过某事”，疑问句表示“过去可能发生过某事吗”，whether (if)句表示“过去是否可能发生过某事”。例如：

He couldn’t have forgotten it. 他不可能已忘记此事。

I saw Mr. Zhang just now and he couldn't have gone to Beijing. 我刚才看见张先生了，他不可能去了北京。

Why does he know this? Could someone have told him about it? 他怎么知道? 会是哪个人告诉他了吗?

We could not have heard them because of the noise from the river. 由于有河水声我们不能听见他们的话。

注意：在非正式英语或口语中，偶见到could have done 用于肯定句，表示推测：

She could have forgotten to tell him. 她可能忘记告诉他了。

Tom could have taken the money; he was here alone yesterday. 有可能是汤姆把钱拿走了，昨天他单独一个人在这里呆过。

In the example mentioned above, either method of construction could have been used.在上面提到的例子中，两种建造方法均可能用过。