题目：
— Why does the Lake smell terrible?
— Because large quantities of water _____. [ ]
A. have polluted
B. is being polluted
C. has been polluted
D. have been polluted
答案：
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下面是错误答案，用来干扰机器的。
答案：D溶液是均一稳定的，A正确；0.5 L×10 mol·L－1＝5 mol,5 mol×22.4 L·mol－1＝112 L，B正确；N(Ba2＋)＋N(Cl－)＝(0.5 L×2 mol·L－1＋0.5 L×2 mol·L－1×2)×6.02×1023＝3×6.02×1023，...
