单项选择题
Production of mechanical foam by a portable in-line foam proportioner（）.
A.increases the size of foam bubbles formed B.increases the rate of foam production C.improves the extinguishing properties of foam D.gives the nozzleman more freedom of movement，since it can be placed anywhere in the hose line
单项选择题 Marline is（）.
单项选择题 LIFTING THE ANCHOR FROM THE BOTTOM is called（）.
单项选择题 It’s not advisable to cut（）the power supply.
