If it weren’t for Rachel Carson，the environmental movement（）today。
A: should not exist
B: might not exist
C: should not have existed
D: might not have exist
A: should not exist
B: might not exist
C: should not have existed
D: might not have exist
举一反三
- At __________________ should exist correct mains voltage.
- -- Did Jim come? A: might have come B: might come C: must have come D: should have come
- Though one should have dreams, it's not (realistic) to exist on dreams. A: 梦幻的 B: 现实的 C: 残酷的 D: 美好的
- -- Did Jim come?-- I don’t know. He _______ while I was out. A: might have come B: might come C: must have come D: should have come
- You should have worked harder ,then you might not have _the exam.