（）is halfway between the forward and after perpendiculars and is reference point for vessel construction.

Which of the following shall not the officers in charge of the navigational watch do?（）

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（）.

Which of the following is not a form of precipitation?（）

The company should establish and maintain procedures to control all documents and date which are relevant to（）.

（）is where the crew eat their meals.

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

Manoeuvring information can not be obtained from（）.

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