题干
选出与你听到的句子意思最相近的句子（ ）
A：Don't laugh at anybody though they make a mistake.
B：Don't agree with anybody because they are wrong.
C：Don't talk about anybody when they are not here.
答案(点此获取答案解析）
A
N2O4，所得混合气体中NO2的体积百分含量为40%，此时，混合气体的平均分子量为
