下列哪项处理可预防迷走神经反射()
A.手术操作轻柔
B.充分通气,避免缺氧与二氧化碳蓄积
C.充分剂量的阿托品
D.用局部麻醉药阻滞迷走神经
E.上述全部
参考答案:E
TCP/IP层次结构有哪些组成?()
A.链路层
B.应用层
C.网络层和网络接口层
D.传输层
—Why didn’t you go to play football with us yesterday afternoon?
—I _____my mother with the housework then.
A.helped
B.was helping
C.had helped
D.have been helping