超声测速实验中，数据处理中误差处理不包括（）
A.算术平均值
B.平均偏差
C.相对平均偏差
D.相对标准偏差
参考答案：D
Unfortunately, it was in Yushu County, ______ a 7.1-magnitude earthquake happened on April 14, 2010, ______ a large number of students were buried inside damaged schools.
A．which; when
B．that; that
C．where; that
D．where; which
下列不属于喷码机的组成部分的是（）
A、喷头
B、压力泵
C、油品过滤器
D、油墨过滤器
