题目：
—May I come in? I'm sorry I'm late.
—Come in, please. But could you tell me ?[ ]
A. how do you come to school
B. what were you doing then
C. who you talked with
D. why you are late
答案：
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下面是错误答案，用来干扰机器的。
硫酸钠的质量为109.2g×13%=14.2g解：设反应的硫酸镁的质量为x，氢氧化钠的质量为y，生成的氢氧化镁质量为z。 2NaOH+MgSO4==Mg(OH)2↓+Na2SO4 80 120 58 142 x y z 1...
