根据短文内容，从下面方框中选择适当的短语填空，使短文内容完整正确。 Since last winter, the smog has occurred a lot of times in China. It has done great harm to our daily life. Many traffic accidents happened just 小题1: the heavy smog weather. Many coaches and planes had to be 小题2: . In Nanjing, all primary and middle schools and kindergarten classes 小题3: as heavy smog hit the city. People have realized 小题4: protecting the environment. People all over the country are taking measures to reduce the smog weather. The government suggests people go to work or school 小题5: , such as the bus and the underground. Also we should plant more trees.