单项选择题
A. 穿过一条交通繁忙的街道时，千万要小心。 B. 穿过一条交通繁忙的街道时，你不能不小心。 C. 在你忙着过街道时，你千万要小心。 D. 在你忙着过街道时，你永远不能不小心。 E. 你永远不要太小心当忙于过街道时。
A. can sell it back to the automobile manufacturer B. can’t buy a new car unless you recycle your old one C. can send it to the government for recycling D. must separate it into metals, plastics, glass, etc
A. Drug use among American teens is increasing dramatically despite years of anti-drug campaigns. B. Drugs are more readily available and used by young people at a younger age than ever before. C. Few parents warn their children often about the dangers of drugs. D. Even policymakers, school officials find it necessary to reexamine current drug prevention efforts.