完形填空（10分，每小题1分）
Nearly every town in America has a post office. Some are very small and you may _____ them near a shop, and _____ are in big buildings. From Monday to Friday, they are usually ____ from 8:30 a.m. to 3:30 p.m.
If you don’t know how much you should _____ for your letter, you can ask the worker. The prices of stamps are _____, from one cent to some dollars. If you want your letter to go _____, write on the envelope（信封）that you want it to go by _____or use an air-mail envelope. But the price will be _____. At a post office you can _____ buy postcards. A postcard is cheaper than a letter. It is an easy way to _____ letters to friends in different places. It is also a cheap way.
A. say    B. find     C. hear
A. others   B. all     C. both
A. closed   B. free     C. open
A. cost    B. spend    C. pay
A. same    B. different    C. easy
A. carefully   B. slowly    C. fast
A. air    B. bike     C. car
A. low    B. small     C. high
A. never    B. also     C. only
A. send    B. show     C. make