一、动词ing形式作主语的几种情况
1．动词ing形式作主语通常表示抽象性、经常性以及习惯性的动作，谓语动词要用单数。
Going to Hangzhou by train takes about 10 hours from here.
从这儿乘火车到杭州大约要用10个小时。
Doing is better than wishing.干比空想好。
2．动词ing形式作主语，且主语较长时，为了平衡句子结构，通常用it 作形式主语。常见句式如下：
It is a waste of time trying persuading such a person.
试图说服这样一个人是浪费时间的。
It is no good eating too much sweet food.
吃太多的甜食没有好处。
3．在There is no结构中，通常用动词ing形式，意为“不可能，没有”。
There is no joking about such a matter.
这种事开不得玩笑。
There was no knowing when he would leave .
无法知道他什么时候离开。
[即时演练一] 单句语法填空
①Walking (walk) every day does good to your health.
②It's a waste of time playing (play) video games every day.
③Watching (watch) too much TV does harm to our eyes.
④It is no use reasoning (reason) with such a stubborn person.
⑤Planning so far ahead makes (make) no sense — so many things will have changed by next year.
⑥There is no denying (deny) the fact.
