读课文，写一写。

1. An email is a message. It goes from _______________.

2. To write an email, you should click on "         __________ ".

3. After you write your message, you should click on "_     _________ ".

4. Then, the message will                         another computer.

“水旱从人，不知饥馑，时无荒年，天下谓之‘天府’也。”从历史上看，促使成都平原成为天府之国的重要水利工程是 [ ]

A．都江堰

B．大运河

C．六辅渠

D．白渠