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

A tide is called diurnal when（）.

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

When steering by autopilot,how often should the steering be checked?（）

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

ECDIS must be able to perform all of the following EXCEPT（）.

Where would you find information about the time of high tide at a specific location on a particular day of the year?（）

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

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（）.