读短文，用所给动词的适当形式填空。

     When you send a postcard, you have to 1_____ (put) stamps on the envelope or on the card. When did

people first begin 2_____ (use) stamps? Who was the first 3_____ (think) of this idea? In the early century,

people 4_____ (not use) stamps. They had to pay postage whenthey received it. Rowland Hill was a school

teacher in England. He was the first to think of 5_____ (use) stamps in the 1850s. He thought it would be

easier for people to use the stamps. Now we know