The safety valves are mounted in pairs

1、Safety valves on a boiler vent to the

Safety valves on a boiler vent to the （）.Afuel tankBbilgeCatmosphereDauxiliary exhaust line

2、（） are mounted in pairs to protect the

（） are mounted in pairs to protect the boiler against overpressure.ASafety valvesBWater tubesCSteam stop valvesDBlow down valve

3、The（） is fitted in pair one is the mai

The（） is fitted in pair one is the main valve, the other the auxiliary or standby.Amain stem stop valveBauxiliary steam stop valveCfeed check or control valveDblow down valve

4、The needle valve in the injector （） at

The needle valve in the injector （） at a pre-set pressure which ensures that the fuel will atomize once it enters the cylinder.Awill liftBwill be liftedCwill closeDwill be closed

5、The needle valve in a fuel valve will

The needle valve in a fuel valve will （） when the fuel pressure action on the needle valve tapered face exerts a force lower than that of the spring compression.Abe jammedBbe openedCbe seatedDbe broke

6、Some cranes are mounted in pairs on a

Some cranes are mounted in pairs on a common platform. which can be rotated through_____.A360oB270oC180oD90o