单项选择题
The brickwork surrounding the firebox of a boiler is known as（）.
A.refractory B.the screen wall C.the water wall D.fire plate
单项选择题 The blocking or absence of fire dampers can cause（）.
单项选择题 The bilge pump on a fishing vessel（）.
单项选择题 The best method of extinguishing a class A fire is to（）.
