The dew point temperature is（）.

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

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

Berthing means bringing a vessel to her berth until（）.

The helm command PORT TWENTY means（）.

The ISM code is part of（）.

A tide is called diurnal when（）.

The mean draft of a ship is the draft（）.

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

Full details of all lights and fog signals are shown on（）.