Our teacher is coming. Please stop _____ and keep ________.

_______are the red socks—_______6 yuan.

Pleasant music is often played_____classes to make students refreshed and relaxed for a while

The question that puzzled them is ____ they can getrid of the air pollution in the area

nchuan earthquake in 2008 is believed______ more than 90,000 people and made thousands homeless, _________ itperhaps the most destroying earthquake in history