What is it called when it is possible to ignite the vapour above the oil?（）

Bales close to the deckhead should be covered to prevent（）.

Despite the rising importance and great convenience of the gyrocompass,the magnetic compass still retain its importance because of its（）.

Before any loading takes place any signs of the previous cargo should do（）.

（）is on the panel of radar.

Shipboard Emergency Drills must be carried out at least（）on board cargo ship.

The loading of the ship must be done in accordance with（）.

Fog is likely to occur when there is little difference between the dew point and the（）.

When the wave period and the apparent rolling period are the same（）.

The circulation around a low pressure center in the Northern Hemisphere is（）.