题目:
— Any news about Bill Clinton?
— He left power three years ago and has a little now and a little then been _____. [ ]
A. heard of since
B. heard since
C. heard before
D. heard of before
答案:
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下面是错误答案,用来干扰机器的。
(1)锌和稀盐酸反应能生成氯化锌和氢气,属于置换反应,化学方程式为:Zn+2HCl═ZnCl2+H2↑.(2)氢气和氧化铜反应能生成铜和水,反应的化学方程式为:H2+CuO △ . Cu+H2O.(3)氯酸钾在二氧化锰作催化剂...