21.---We can’t expect _____blue sky unless we create ____less polluted world.
A. a; a B. a; the C. the; a D. the; the
22. ____he lost the game was _____we hadn’t expected.
A. That; which B. That; what C. Whether; that D. Why; that
23. He managed to ____him of the disease.
A. treat B. look after C. cure D. take care of
