—I'm hungry. Could you please give me something to eat ?—Of course. Here are some ____________.

He goes to work by bus, but he walks___________ after work.

It is our ________ to look after our parents when they get old.

-You look so worried, what’s wrong?  -More and more people like me begin to worry about the ______ pollution after the haze (雾霾) appeared in Beijing and some other cities in China. 

---How many _______do you have？　　　　　　---Let me see, my father has two brothers.