A 形式

to be+现在分词：

He seems to be following us．

他好像在跟着我们。

B 用法

不定式的进行式可用于：

1 助动词之后：

They’ll be wondering where you are．

他们会纳闷你在哪里。

—He may／might be watching TV．

—He can’t／couldn’t be watching TV．

—他可能在看电视。

—他不会在看电视。

There are no programmes today because of the strike．

由于罢工，今天没有节目。（否定的推论）

He must be coming by bus．

他一定是乘公共汽车来。（推论）

You shouldn’t be reading a novel．You should be reading a textbook．

现在你不该看小说，你应该看课本。

2 appear，happen，pretend，seem之后：

He appears/seems to be living in the area．相当于：

It appears/seems that he is living in the area．

（看来）他似乎就住在这一带。

He appeared／seemed to be living in the area．相当于：

It appeared／seemed that he was living in the area．

当时（看来）他似乎就住在那一带。

I happened to be standing next to him when he collapsed．相当于：

It happened that I was standing next to him when he collapsed．

他倒下的时候我恰巧站在他旁边。

He pretended to be looking for a book．相当于：

He pretended that he was looking for a book．

他假装在找书。

3 hope和promise之后，或agree，arrange，decide，determine／be determined，plan，undertake之后，但用于hope和promise后更常见：

I hope／hoped to be earning my living in a year’s time．相当于：

I hope I will／I hoped I would be earning…

我希望在一年内能自食其力。

determine/be determined，plan等词可代替上面句子中的hope，然而意思稍有不同：

I promised to be waiting at the door when he came out．

我答应在门口一直等到他出来。

agree， arrange， decide， determine／be determined， plan， under－take等词可代替上面句子中的promise，意思各不相同。

4 在被动时态的 believe， consider， suppose， think等之后：He is believed to be living in Mexico．

据信他现在住在墨西哥。（参见第306节。）