輪機(jī)英語船舶輔助機(jī)械單項(xiàng)選擇題每日一練(2019.01.16)

來源：考試資料網(wǎng)

1 The safety valves should be tested and adjusted when the boiler survey is （）

2 When operating with a negative suction head, which of the following types of pumps will require priming?（）

3 To correct the condition of slugging and flooding back in a refrigeration system, it may be necessary to （）.

4 The output volume of a positive fixed displacement pump can be changed only by （）.

5 If an electric motor driven air compressor fails to start, it may be due to a （）.