The Earth’s irregular heating is caused by （）.

In Admiralty Sailing Directions，bands is the word used to indicate（）marking．

Attention is called to the fact that in many cases pipelines are not （） and charted depths may be decreased by up to 2 meters．

Information on the operating times and characteristics of foreign radiobeacons can be found in which publication? （）

Due to lapse of time the risk in these areas to surface navigation is now considered （）than the ordinary risks of navigation，but a very real risk still exists with regard to anchoring，fishing or any form of submarine or seabed activity.

On a voyage from Capetown to London，the favorable ocean current off the coast of Africa is the （）.

The distance between any two meridians measured along a parallel of latitude （）.

Lateral movement of the vessel to leeward of its course defines （）.

A vessel is entering port A for the first time and has a Pilot conning the vessel. The Master is unsure that the Pilot is taking sufficient action to prevent a collision. What should the Master do（）.

Clearance gauges at bridges indicate （）.