电子邮件与传统邮件相比，最大的优点是( )。
A．速度快
B．距离远
C．价格低
D．传输量大
参考答案：A
解析： 电子邮件是指利用通信系统和计算机网络传递的邮件，与传统邮件相比最大的优点是速度快。 相关知识点： 电子邮件系统设有邮件服务器、电子邮箱，并且规定了电子邮件地址的书写规则。E-mail是一种利用网络交换文字信息的非交互式服务。使用 E-mail需要两个服务器。发信服务器把电子邮件发出去：收信服务器接收他人的来信并且保存，随时供收件人阅读和变更。
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| When you are having class in the early morning, it is not unusual to notice your classmate sitting beside you yawning. He 1 that he didn't have a sound sleep the night before. Many 2 don't get adequate sleep because they are burdened with too much homework, which keeps them up at night doing countless exercise. Some teens cannot 3 at night even when they want to so much. Researches show that during your teenage years, the body's biological clock is ___4_ ,telling you to sleep later at night and wake up 5 in the morning. But 6 in the body clock aren't the only reason teens lose sleep. Lots of people have insomnia(失眠). The most common cause of insomnia is 7 . But all sorts of things can lead to insomnia, including 8 discomfort, emotional troubles and even sleeping environment. It's common for everyone to have insomnia occasionally. But if it 9 for a month or more, go and consult a doctor. Most teens have 10 sometimes, which may make you sweat. But, if they are too frequent, a person's sleep pattern can be seriously 11 . The most common cause of them is emotional 12 , such as fear, stress or anxiety. If you have them a lot, you're also supposed to talk to a 13 . Medical specialists encourage teens to make lifestyle changes to help them develop good sleeping 14 . Most probably you know that a cup of coffee can keep you 15 at night, but did you know that playing video games or watching TV does the same? | |||
| ( )1. A. yells ( )2. A. adults ( )3. A. study ( )4. A. broken ( )5. A. sooner ( )6. A. changes ( )7. A. happiness ( )8. A. mental ( )9. A. helps ( )10. A. nightmares ( )11. A. improved ( )12. A. issue ( )13. A. doctor ( )14. A. idea ( )15. A. asleep | B. proves B. teens B. work B. reset B. earlier B. moves B. joy B. physical B. reports B. dreams B. destroyed B. affair B. desk-mate B. habits B. alive | C. claims C. parents C. sleep C. repaired C. quicker C. patterns C. stress C. biological C. stops C. stress C. advanced C. problems C. teacher C. time C. awake | D. complains D. teachers D. communicate D. damaged D. later D. model D. homework D. medical D. lasts D. change D. affected D. things D. friend D. environment D. annoyed |