高中英语语法学习 替代动词

　　1.do/does/did替代动词

　　If thats the case then 100,000,000,000,000,000,000,000 people would weigh as much as the whole Earth

　　does.(= weighs)

　　Difficulties strengthen the mind, as labour does(= strengthen) the body.劳动锻炼身体，困难锻炼意志。

　　A feather falls slower than a stone only because the air holds the feather back more than it does the stone.(替代)

　　2.so和not分别代替肯定和否定的从句(常用动词：think,believe,suppose,imagine,expect,guess,be afraid,fear,hope.etc.)

　　Is he coming?

　　I suppose so./So I suppose.

　　否定：I suppose not.