这道题选a,为什么不选b啊

这道题选a,为什么不选b啊 i _____hardly tell you how badly i feel about her departureA need B could C shall D could下面这两道题目为什么第一题选c 第二题选a？1.the boy was at a loss what to say .He ____the quedtion asked by the policemanA might not understand B would not understandCmight not have understood D would not have understood 2you _____ there to work as a volenteer since you are not in good healthA needn't go B needn't have gone