你可能感興趣的試題

The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs, is to （）.

A.secure and tag the electrical circuit
B.place a crow bar in the flywheel of the unit
C.inform all persons in the area not to start the unit
D.make a log book entry

單項(xiàng)選擇題

One of the main differences between the various types of screw pumps is in the （）.

A.stuffing box diameter
B.direction of rotation of the screws
C.pitch of the screws
D.type of driving gears