题目

水溶液中能大量共存的一组离子是A. B.C. D. 答案：【答案】C【解析】A．与结合生成沉淀而不共存，A不选；B．与结合生成或而不共存，B不选；C．、、、四种离子之间不反应，能大量共存，C选；D．与结合生成而不共存，D不选。答案选C。---Do you know where Tom is? I have to talk to him. ---Sorry, he_____ Japan. But he____ in two days. A．has been to; will come back        B．has gone to; will be back C．has been in; would come back     D．has gone to; won’t come back