Not until the train pulled into the station ______ that his suitcase was gone.

—I think the environment is becoming worse.
—Yes, I really don’t know            we can do about it.

We all think it is Jack, rather than his parents that           responsible for his bad manners in public.

The news shocked the whole nation         a strong earthquake hit Yushu on Apr.14, 2010.

It was about 600 years ago _______the first clock with a face and an hour hand was made.

We must keep in mind the fact __________ China is still a developing country.

Only when _______ hard _______ make your dream come true.

When it comes to relieving stress, proper rest and good nutrition can help, _______.

While watching television, __________.

Thomas wants to know ______Nina lives.