茨流量计水平安装时,流量计进口端轴线不得低于管道轴线,以免介质中的脏污杂质滞留于流量计的()内,影响正常转速.
A.磁耦合器
B.甩油环
C.计量室
D.储油器
参考答案:C
Don't touch anything in the lab _____ your teacher tells you to.
[ ]
A. if
B. though
C. unless
D. even though
下列属可再生资源的有( )
A.森林
B.煤炭
C.铁矿
D.核能