凡是跑道具备（）条件的都应提供精密进近地形图。

In TAF, BR stands for （ ） .

（ ） are least likely to contribute to structural icing on an aircraft.

（ ） clouds have the greatest turbulence.

（ ） is the weather phenomenon that signals the beginning of a thunderstorm.

The three stages of a thunderstorm are （ ） ．

（ ） is not included in the three conditions necessary for thunderstorm formation.

An area of severe weather often forms well （ ） the fast-moving cold front.

（ ） would decrease the stability of an air mass.

When the temperature rises, first of all,

Airmasses are classified according to the regions where they originate. They are generally divided into polar or tropical to identify （ ） characteristics.