随机误差的特点主要有三个：（）、对称性和抵偿性。
参考答案：有界性
油系统失火不可用水灭火。
Steve has to get up at 5:00 A.M. to get to school. ______ this , he has never missed a class.
A. In contrast to B. Apart from C. In addition to D. In spite of
