to后面加动词时一般都是动词原形，什么时候to后面可以加动词的ing形式呢?
EX. I look forward to talking to you on Friday afternoon.
例句：我期待下周五与你的谈话。
As the example above shows， sometimes it is correct to use “to” plus the –ing form of a verb.
从例句里我们可以看到，有时“to”也可以加动词-ing形式。
Many non-native English speakers are reluctant to use –ing after “to”。 Maybe this is because you learnt at school that after “to” a verb should always be in the infinitive.
许多非英语国家的人都不喜欢在“to”后面加动词-ing形式。这可能是因为你们学校里的老师告诉你们“to”后面一般都跟动词不定式。
This is only half true. “To” actually has two uses – EITHER as an infinitive marker (e.g. The Company wishes to purchase the shares)， OR as a preposition (e.g. He has gone to lunch)。
其实不然。事实上“to”有两种用法，一种是动词不定式的标志(比如：这家公司想要收购股份。)，另一种，用作介词。(比如：他去吃饭了。)
When “to” acts as a preposition it is usually followed by an –ing form (which in this case is a gerund) or a noun/noun phrase， as in these examples：
当“to”作介词时，后面通常会跟着动词-ing形式(动名词)或者名词/名词词组，比如：
EX1. There is no obstacle to registering the company.
EX2. There is no obstacle to the registration of the company.
例句：注册这家公司没有困难。
EX1. I do not recommend committing yourself to purchasing the shares yet.
EX2. I do not recommend committing yourself to the purchase of the shares yet.
例句：我现在还不建议你去收购那些股份。
EX1. I look forward to hearing from you.
EX2. I look forward to your reply.
例句：我期待你的回复。
There are， of course， exceptions to this rule. The next post looks at these.
当然，“to”加动词-ing也有例外的时候。敬请期待下次更新。