The best method to________this goal is to unite as many sympathetic people as possible with the labor movement itself.[ ]

What’s the trouble with you一I________ a headache.

I’m considering________to Qingdao for my holiday by train.-Why not try________by ship for a change?[ ]

Nowadays a lot of teenagers have been _____ surfing the Internet.[ ]

With the development of the Internet, _______ communication is done by regular mail.