某有色溶液中，可能大量存在Ag⁺、H⁺、Cu²⁺、CO₃^2-、OH^-、Cl^-，你认为一定有的离子是______，一定没有的离子是______，还需进一步确认的离子是______．

At present, many people from countryside went to the cities ____better job.

A．in search of

B．in place of

C．in memory of

D．in spite of