对于采用螺纹连接的管路,公称直径也可用英制长度单位(in)表示。那么DN4〃表示公称直径为()mm的管路。
A、80
B、100
C、125
D、150
参考答案:B
Grover Cleveland was the first president ________in the White House.
A.got married
B.to get married
C.has got married
D.was married
蒸汽往复泵启动时主蒸汽管线声音异常时如何处理?