题目

. We’d like to do _______ we can _________ the poor.    A. how; help  B. whatever; to help   C. whatever; help   D. however; to help 答案：B下列各组离子，可以大量共存的是（  ）A．K+、NH4+、OHˉB．Na+、Ba2+、SO42ˉC．SO42-、Mg2+、NH4+ D．Clˉ、Fe3+ 、Ag+