题目

The conference has been held to discuss the ________ of global warming on people's lives all over the world. () A . importance B . effects C . protection D . attitudes 答案：B 下列各组离子能在溶液中大量共存的是 A． Ca2+、、H+、Cl－ B． Ca2+、K+、、OH－ C． OH－、Cl－、H+、 D． Na+、Cu2+、Cl－、