No one can deny that it is ______ that many more residents could have been injured if the building had fallen at midnight.

So far we have done a lot to build a low-carbon economy, but it is _____ idealWe have to work still harder[ ]

Is it that you often play computer games ________ worries yourparents

Tom is the only one of the students who ____ going to swim this afternoon.

air quality in urban areas from one to five:excellent, fairly good, slightly polluted, poor, and dangerous