Who’s that boy —Liang Bo. Heis___ very popular singer in Voice of China.

____________ Davy called me, I was sleeping.

With Father’s Day around the corner,I have taken some money out of the bank________ presents for my dad. [ ]

John was born _______ June 6, 1985.

许多同学都有自己的电子邮箱，如168@sina.com, pgbook@ 163.com, hifriend998 @ 126.com 等。请问其中的@表示什么意思，该怎么读