E-mail is a valuable _____ for college students at any level.
The police have ____ power to deal with such matters by ____ law.
—It’s cloudy outside .Please take an umbrella .— .
The OPEC has recently cut back production and the price of oil has been ______ to $90 a barrel (桶).
_____ is expected, according to the survey, is that prices of houses will not go up any longer.
____ I want to know is ____ I can master English in the shortest possible time.