II. 动词-ing形式的用法复习 1. 动词-ing形式在句中作主语 1) Traveling abroad is very exciting. 2) Learning new words is very important for me. 3) It is no use crying over the spilt milk. 4) It is a waste of time watering the garden when it is raining. Conclusion: 动词-ing形式作主语可直接置于________(句首/句中/句末)主语的位置，也可用it作__________, 而把真正作主语的动词-ing形式放在句子后面。

句首

形式主语