单选题 The following famous social networking sites, which one is easy to be visited in China?

单选题 When you get an e-mail in the mailbox, you will see the ______ first;

单选题 E-mail is a system for ______ electronic messages.

单选题 Which one is the closing sentence in an e-mail?

单选题 When you want to send company catalogue by e-mail, you have to use ______

填空题 Thanks for your e-mail. ____________ (我方报价如下).

单选题 Which communication tool can only be used by VPN in China?

填空题 We are interested to your QQ kite, ____________ (请提供产品目录单和报价单).