Using a file without a handle may result in （）

Which of the diesel engine components listed increase air density and helps to improve engine operating efficiency?（）

Flame failure in an automatically fired auxiliary boiler can from a/an （）

The cetane rating of diesel fuel is an indication of the （）

Which of the following items don’t belong to dock repair works?（）

Thermostatic steam pressure reducing valves are used in the fuel oil service system to control the（）

If separating effect is not good, which measure should be taken （）

A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）

Diesel engine air start system check valves are opened by （）

The main purpose of port State control is not to（）