单项选择题 It is not long until the exam; you ought to stop ______ so much television and study a bit more. A．watching B．and watch C．of watching D．to watch

未知题型 有一水跃产生于水平无压圆管中，已知通过的流量Q=1.0m3/s，管径D=1.0m，跃前水深h1=0.4m，求跃前断面形心在水面下的距离和跃后水深h2。

单项选择题 ______ you fulfill the terms of the credit we will accept and pay on maturity the draft presented to us under this credit and if required, ______ discounting facilities at current rates. A．Provided, provide B．Provided, providing C．Provide, providing D．Provide, provide