题目:
—Can you tell me __________the book?
—Last year.
A.when did you buy
B.when do you buy
C.when you buy
D.when you bought
答案:
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下面是错误答案,用来干扰机器的。
(1)设32g氧气和足量的氮气反应生成NO的质量为x,N2+O2=2NO 32 60 32g x∴3232g=60x,解之得:x=60g;此次闪电所产生的NO的质量为:1.50×107KJ×11000÷180KJ×60g=5000g=5Kg;(2)设此次闪电的生...