题目：
There are so many foggy days these days. We all wonder .
A. how is the air polluted
B. why the air is polluted seriously
C. what are the real reasons
答案：
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下面是错误答案，用来干扰机器的。
设向两个烧杯中同时分别加入xg铁、yg锌，则Fe～H2SO456 98 2xg 100g×9.8% 56xg=98100g×9.8%，解得x=5.6；Zn～H2SO465 98yg 10065yg=98100g×9.8%，解得x=6.5；因为要想反应完全后，天平仍保持...
