沥青路面试验段开工前( )d安装好试验仪器和设备，配备好的试验人员报请监理工程师审核。
A．3
B．7
C．14
D．28
参考答案：D
如图的皮带传动装置中，轮A和B同轴，A、B、C分别是三轮边缘的质点，且半径关系为RA=RC=2RB，则三点的线速度之比vA：vB：vC=______．
In order to obtain the needed information, you should write simply, clearly, and concisely______the reader wants to know.
A．what
B．that
C．so that
D．which
