文中共有10处语言错误，每句中最多有两处，每处错误仅涉及一个单词的增加、删除或修改。
增加：在缺词处加加一个漏字符号（Λ），并在其下面写出该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1. 每处错误及其修改均限一词。
2. 只允许修改10处，多者（从第11处起）不计分。（试题内容见答题卡）
Dear teachers and students,
As we know, air pollution is serious environmental problem in our city. Every day we had to take in very dirty air, which isn’t good for our healthy. To make sure the air fresh, we should keep the following suggestions on mind. Firstly, we should take a bus or ride a bicycle as much as possible instead of drive a car. Secondly, we shouldn’t throw litter here and there but put them into the dustbin. Thirdly, some factories should be closed and moved out of the city. Finally, we need to plant many trees to make the air fresher. Let’s take action and try your best to make the air in the city cleaner!
Thank you!
The Students’ Union