senior high school English
1.什么情况用have什么情况用have been?
a lot of factories____
have been set up对 have set up错
set up 好像是点动词词组吧.怎能用been?
2.their duty is to__their country against foreign enemies's attacks.
A defeat B defend 咋选B
3.Coal was formed out of dead forests by chemical__.
A processes B product 咋选A