根系吸水的主要动力是()。
A.根压
B.蒸腾拉力
C.主动动力
D.被动动力
参考答案:B
-Did you punish him for losing your digital camera?
-Yes, but I don't think I ________.[ ]
A.should do that
B.need to have done so
C.ought have done that
D.should have done so
因特网上提供的服务有很多,以下不是其中的服务是()
A、传真
B、IP电话
C、在线电影
D、QQ电影