以下哪一种文体属于公文。（）
A.散文
B.通知
C.计划
D.总结
参考答案：B
______ once every two years, whether it is a car, a bus or a lorry, is the rule that all drivers must obey in our country.
A．Having been examined
B．Examined
C．Examining
D．Being examined
甲醇废液如何处理？
