Fred entered without knocking and, very out of breath, sank _______ a chair.
—Skipping breakfast is a great way to lose weight.— . Actually it has the opposite effect.
This is a kind of traditional classroom teaching students are taught a lot about grammar rules.
—Shall I turn the heating on?—Sure, it's so cold in here. I'm freezing.
The No. l subway, at the end of 20l4, will greatly improve the traffic conditions in Qingdao.
Air pollution is getting more and more serious, so we must take action it is too late.