—How much are the two pairs of shoes?  —They are not expensive. I think fifty dollars ______ enough.

There     some milk and eggs on the table.

E－mail,as well as telephones,　　an important part in daily communication.

The university estimates that living expenses for international students________around $8,450 a year，which________a burden for some of them.                     (2013·湖南，33)

--_____ of the population of the city _____workers? --About 60 percent.