题目内容：

    The year is 1971. Ray Tomlinson is sitting in his office in Cambridge, Massachusetts. He types a few letters on a keyboard. Then he moves to a second computer in the room and reads the monitor. He just sent the first electronic message from one computer to a different computer through a network.

What did this first e-mail say? Tomlinson doesn't remember. Maybe it was just a string ( 串 ) of letters, like "q w e r t y u i o p." He does remember the second message. He sent it to his co-workers. This second e-mail message told people how to send e-mail on the computer network.

Before 1971, people only had keyboards monitors, which were all connected to a computer,  at their desks. People could only send messages to other people on the same computer. They could send files (文件) to other computers through the network, but they couldn't "talk".

To solve this problem, Tomlinson needed a way to direct messages to the right person on the right computer on any network. He chose the @ symbol to separate a person's name from  the name of the computer the person was using. The @ symbol was a good choice. This symbol was not in anyone's name. Few people used it. In fact, typewriter companies thought about taking it off the keyboard.

In the 1970s, only about 500 people used e-mail to do projects at work. Then, in the 1980s, the first personal computers arrived. For the first time, people could have computers at home.  Then cane the Internet: Soon e-mail became a popular way to communicate. Today, over one billion people use it.

Tomlinson is sorry about one thing － spam. Most of it is advertising that tries to sell something. As much as 70 percent of each day's 180 billion e-mail messages is spam. As the number of e-mail users grows, spam is becoming more and more of a problem.

Pitifully, Tomlinson never made any money from e-mail and most people don't even know his name. However, thanks to this unknown hero, people all over the world can communicate with each other in seconds.

1.What can we learn about Tomlinson's first e-mail?

A.It had several files attached. B.It was just a test message.

C.It was an e-mail usage warning. D.It came from one of his co-workers.

2.What happened before e-mail?

A.There wasn't  the @  symbol  on  the keyboard.

B.Personal computers had been networked.

C.Not many people used the @ symbol.

D.Computers had been used at home.

3.What did the public think of e-mail in the 1970s?

A.They were against it. B.They thought highly of it.

C.They paid little attention to it. D.They had high expectations for it.

4.What does "spam" probably refer to?

A.Unfinished e-mail. B.Unknown e-mail.

C.Unwanted e-mail. D.Unfamiliar e-mail.