Atmstrong公理系统中有一条推理规则为：若X→Y为F所逻辑蕴涵，且Z⊆U，则XZ→YZ为F所逻辑蕴涵。这条推理规则称作（）。

The sound of the water gently______against the side of the boat was very pleasant.A．creakingB．surgingC．suckingD．lapping

A.
A．creaking
B．surging
C．sucking
D．lapping

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A．Throw himself in front of the train.B．Throw himself against the bus.C．Squeeze himself between the rails.D．Strike himself with the flowerpot. 点击查看答案