--Wow, ____useful and fashionable iphone5s you have bought!
---Yes, it is ____ great help to me, ____ I must say it also cost me a lot.

---I hear the government is going to ___ the air quality with the new standard PM2.5，isn’t it？
---Yes, ___ the air pollution will get more serious.

_____ you can understand how the human body woks, you need to have some knowledge of chemistry

I think that “Duang” must be one of the words on the Internet this year.

---Why did you buy one more tie？you have got more than ten ties,
---A man can never have _____ many ties.