Unit 7 Protect the Earth 习题2一、 单项选择。1. - What _we do to save energy?- We should not drive so much.A.keepB.shouldC.makesD.cans2.- How should we save plastic bags and bottles?- We should more paper bags and glass bottles.A.use B.usesC.canD.keeps3. We wood make tables chairs and many other things.A.use; andB.uses; toC.use; toD.uses; for4. We cut too many trees because trees help us keep the air clean.A.shouldB.should notC.canD. keep5. There is not much coal or oil on , so we save energy.A.earth; shouldB.Earth; should notC.Earth; shouldD.earth; should not