Which sentence is grammatical correct? ( ) A: It takes seventeen trees to produce one ton of junk mail. B: It takes seventeen trees to produce one ton of junk mails. C: Mails are just sent once a day, and there is no delivery on Sundays or holidays. D: The mail is just sent once a day, and there is no delivery on Sundays or holidays.

After Steven sent some e­mails , he ________ surfing the Internet.

He will send these parcels to me by _____. A: express B: the ca C: mails

Airport is a place for transporting EXCEPT ___________. A: passengers B: cargo C: seats D: mails

If you only for a few minutes to pick up mails, you can unlock your door.

中国大学MOOC: In ancient times the mails were relayed from one place to______.

My mail box is full of ______ mails every day. A: hunk B: junk C: hunks D: junks of

In ancient times the mails were relayed from one place to _______. A: the other B: another C: the others D: other

If you only for a few minutes to pick up mails, you can unlock your door. A: 正确 B: 错误

【单选题】 Clerks in the post office ________ mails according to the places they are to go. A: mysterious B: classify C: harmonious D: luxury