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

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

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

The force resulting from the earth’s rotation that causes winds to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere is called（）.

（）is on the panel of radar.

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

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

The dew point temperature is（）.

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

A tide is called diurnal when（）.