21£®We cannot be     about our work£®Any small mistake may lead to a serious accident£®

A£®very Particular                   B£®too cautious 

C£®extremely considerate            D£®quite serious

22£®My daughter hasn’t been in touch with me for two months£¬and I wonder what has    her£®  

      A£®become of           B£®appealed to    C£®gone against          D£®taken over