调试测量发电机绝缘时，要求单相对地.两绕组间的绝缘电阻值大于（）.
A.5MΩ
B.50MΩ
C.500MΩ
D.2.2GΩ
参考答案：C
He ________this new computer since last week. It is birthday present.
A．has bought
B．bought
C．has had
D．will buy
沥青混合料的三种组成形态为
