The bus hit against a tree in the fog and __________to the deep valley, with ten passengers killed and twenty wounded.

I wonder if the work can be completed in a month.— The work is progressing________schedule and should be completed within three weeks [ ]

Please __________your mobile phone when you are having a meeting.

Every year there are about _______ people waiting for their trains back home in the railway station before Spring Festival comes.

It seems that living green is ________easy and affordable A small step makes a big difference