In communication, a smile is usually ______ strong sign of a friendly and ______ open attitude.

Are you going to Guilin by plane?—It’s fast but expensive, so I’m not sure. I __________ take a train.

16-year-old students in England should understand fifteen _______ words.

Thisbookis_______hard_______understand. [ ]

She lost her temper with a customer and shouted at him.