《2025年成才之路高中新课程学习指导高中英语选择性必修第一册人教版》

2. 形式主语 it 代替动词-ing 形式作主语
为保持句子平衡，可用 it 作形式主语，而将动词-ing 形式放在句末，其逻辑主语泛指人们。
常用此种情况的形容词有 dangerous, worthwhile, useless 等；名词或名词短语有 no use, no good, fun, hard work, a hard/difficult job, a waste of time 等。
It’s no use exchanging the pink dress for a red one, for she likes neither of the colors.
把粉红色的连衣裙换成红色是没有用的，因为她不喜欢这两种颜色。
It is a waste of time persuading such a person to join us, for he is not interested in the topic.
说服这样的人加入我们是浪费时间，因为他对这个话题不感兴趣。
▶联想拓展
It is... + doing sth. 句式荟萃
(1) It is + adj. + doing sth.
It is/feels funny doing sth. 做某事(感觉)很有趣。
It is useless doing sth. 做某事是无用的。
It is worthwhile doing sth. 做某事是值得的。
(2) It is a waste of time doing sth. 做某事是浪费时间。
(3) It is no + n. + doing sth.
It is no good/no use/no fun/no pleasure doing sth.
做某事没好处/没用/没意思/没乐趣。
▶即学即用
单句语法填空
(1) It was great fun walking (walk) along the streets, enjoying the relaxing atmosphere!
(2) It is useless trying (try) to convince her that she doesn’t need to lose any weight.
(3) It is no good staring (stare) at the computer screen for a long time, which will do great harm to your eyes.

答案： 2.
(1)walking
(2)trying
(3)staring