题目

从溴乙烷制取1,2­二溴乙烷，下列制备方案中最好的是                        ( ) A．CH3CH2Br CH3CH2OHCH2===CH2CH2BrCH2Br B．CH3CH2BrCH2BrCH2Br C．CH3CH2BrCH2===CH2CH3CH2BrCH2BrCH2Br D．CH3CH2Br CH2===CH2CH2BrCH2Br 答案： You look very tired, so I think you should stop _____ a rest. [     ]A. to have B. from havingC. havingD. of having