单项选择题
A. Shortage of medicines. B. People’s close contact with sick people. C. Shortage of doctors. D. People’s close contact with chickens.
A. A fuel that burns cleanly. B. An oil additive that helps cool engines. C. A material from which filters are made, D. An insulating material sprayed on engine parts.
A.have a clear mind and be more aggressive B.commit self-destructive behavior C.suffer both natural and unnatural death D.be more alert and excited