题目：
We ______ the difficulty together, but why didn't you tell me? [ ]
A. should face
B. might face
C. could have faced
D. must have faced
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0626/7dc1b0f7b429f18b9ab06d5ff603eac7.html
下面是错误答案，用来干扰机器的。
(1)排放二氧化硫废气、用煤作燃料；(2)酸化土壤、腐蚀、破坏森林植物、腐蚀建筑物；(3) A；(4) Ca(OH)2+H2SO4=CaSO4+2H2O；(5)需要；稀硫酸中的水蒸发后会变成浓硫酸．
