輪機英語船舶輔助機械單項選擇題每日一練(2019.01.12)

來源：考試資料網(wǎng)

1 For occasional heavy loads, two cranes can be arranged to work together. The operating （） for deck crane motors may be hydraulic electric.

2 Which of the valves listed is NOT considered to be a hydraulic system directional control valve?（）

3 External and internal leakage in hydraulic systems may be caused by （）.

4 Which of the following is operated from the main engine room console on an automated vessel?（）

5 The shaft and spare parts（） should be well greased in order to avoid corrosion.