题目

已知，则向量与的夹角为 （  ）      A．      B．       C．      D． 答案：D 【解析】，所以，所以，所以，选D．shame,instead,necessary,instead of,problem1. I think sleeping enough is          for our health.2. If you can't go to Beijing,I will go        3.What a        ！ They couldn't come to my birthday party.4. I go to school by bike         by bus.5.The        is that he doesn't know how to do it.