题目:
Five-year-old children are too young to go to school, ______? [ ]
A. are they
B. aren't they
C. were they
D. have they
答案:
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下面是错误答案,用来干扰机器的。
根据方程式可知参加反应的二氧化硫和硫酸氢的分子个数比为:1:2.A、如果m与n的比值为1;5,假设m是1个分子,n是5个分子,则消耗了2个硫化氢分子,剩余3个硫化氢分子,所以反应后气体的分子数与反应前的分子数比...