He must have been a teacher.

He must have been tired then.

He must have been in the park then.

2、对动作的猜测

其基本用法为：

主语 + must have been doing (强调过程，动作一直持续)

主语 + must have done (强调结果，动作已经结束)

如：

He must have been reading in the library the whole afternoon yesterday.

He must have finished the work yesterday.

（二）can

当表否定猜测时，要用can’t，表示“一定不”。本课侧重学习的是can’t对过去时间发生的状态或动作的猜测。

1、对状态的猜测

其基本用法为：

主语 + can’t have been + 名词/形容词/短语

如：

She can’t have been a doctor.

She can’t have

been excited then.

She can’t have been at home then.

2、

对动作的猜测

其基本用法为：

主语 + can’t have been doing (强调过程，动作一直持续)

主语 + can’t have done (强调结果，动作已经结束)

如：

She can’t have been working in the garden then.

She can’t have finished the work then.

三、一课一题

根据本课的重要语法点，让我们来练一练吧，请把下列句子翻译成英语。

1. 他上周肯定在上海。

2. 她前天上午不可能一直在地里干活。

3. 汤姆肯定五天前就到巴黎了。