It___ how long the shock that explosions hit London transport system will stay in people's hearts.
The big snow caused great _______to the people living in the south of China, ________some of them homeless.
Mr. Smith, ______ in the factory for thirty years, is on the way back to his village.
—How was that? —I was chatting on line _____ the power went out.
Our teacher always speaks slowly and clearly in class _____.
—Are you satisfied with the answer? —Not at all. It couldn't have been ______.