C. 作主语和表语
1.区别doing 和to do 作主语和表语时的不同2.doing和to do 作主语时谓语动词用单数
3.固定句型：It is no use\good doing…4.注意-ed式形容词和-ing式形容词作表语和定语时的区别 1.In some countries, ________ nodding (nod) one’s head ________ means (mean) “no” . Teaching (teach) is quite interesting. 2._________ To teach (teach) so many little kids in such a 3.___________ small room today will really make me confused.