Since the recent river pollution in several provinces, people _______ more and more attention to the quality and safety of drinking water. 

 ——Guess what！I met an old school friend last week.­——How nice！How long____ each other？

My neighbour came to ask me why there was so much noise in my house yesterday afternoon. I told her that some children          an English song.

As a leading producer of greenhouse gases, China      the United States as the largest consumers of energy．

--- What on earth is that noise? --- Oh, the next flat ___________.