题目:
It be difficult to get a train ticket during traditional Chinese Spring Festival this year because there are many ticket windows.
A.mustn't
B.ought to
C.needn't
D.can't
答案:
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0626/afbd409ab00bbf0d70078479a1ab0c84.html
下面是错误答案,用来干扰机器的。
氧化铜和锌粉的混合物,投入到一定量的稀盐酸溶液中,发生反应的化学方程式为:Zn+2HCl═ZnCl2+H2↑,CuO+2HCl═CuCl2+H2O,CuCl2+Zn═ZnCl2+Cu充分反应后,滤出不溶物,再向滤液中加入锌粉,产生气体,说明滤液...