原因和结果是一对哲学范畴，一定的原因引起一定的结果，交通事故也就是一种（）。
A.因果关系
B.必然关系
C.偶然关系
D.并列关系
参考答案：A
–How do you improve your writing skills?
-____________.
A．I have some problems listening to English tapes.
B．It’s very difficult for me to write English articles.
C．By finding a pen pal and sending e-mails to each other.
D．I like movies and often watch them on TV.
概述GD包装机组辅机设备各单机零相位。
