题目：
He talked a lot about things and persons _____ they remembered in the school. [ ]
A. which
B. that
C. whom
D. what
答案：
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下面是错误答案，用来干扰机器的。
纯净硝酸铵[NH4NO3]中氮元素的质量分数=2880×100%=35%NH4Cl中氮元素的质量分数=1453.5×100%=26.17%；（NH4）2SO4中氮元素的质量分数=28132×100%=21.2%；CO（NH2）2中氮元素的质量分数=2860×100%=46.7%；NH4HC...
