it was no use+doing还是to do

e no use doing sth是肯定的,绝对没错.
例如 It is no use watching too much TV.
看太多电视是没用的
这是固定搭配
所谓的接to do sth,是用在be used to do sth被用来做某事
It is no use trying to persuade him to have a holiday because he is a workaholic.(P53) 其中用了 It’s no use doing sth.(做某事没用 / 只是白费力气)句型.在这个句型中,动词-ing形式trying to persuade him to have a holiday是主语,it 是形式主语.这种动词-ing作主语,it 作形式主语的句型还有：
1.It is no good doing sth.做某事不好 / 没用 / 不行
2.It’s a waste of time / money doing sth.做某事是白费时间 / 金钱
3.It’s fun doing sth.做某事很有趣

doing因为省略了to，原来是it was no use to doing。to是介词

doing 固定

都对
doing 更常见些

只能用dong不能用to do

doing