11、There is no denying the fact that air pollution is an extremely serious problem：the city authorities should take strong measures to deal with it.
12、An investigation shows that female workers tend to have a favorable attitude toward retirement.
13、A proper part-time job does not occupy students' too much time. In fact，it is unhealthy for them to spend all of time on their study. As an old saying goes：All work and no play makes Jack a dull boy.
14、Any government，which is blind to this point，may pay a heavy price.
15、Nowadays，many students always go into raptures at the mere mention of the coming life of high school or college they will begin. Unfortunately，for most young people，it is not pleasant experience on their first day on campus.