自动相关监视主要使用的或者是最佳的通信链路是（）。

The highest VHF frequency of radio communication between air and ground is （ ） .

The lowest VHF frequency of radio communication between air and ground is （ ） .

（ ） is the accepted standard for worldwide time signal broadcast used for aviation.

（ ） means the level is measured in 1013.2 pha.

An aircraft known or believed to be in a state of emergency should be given（ ） over other aircraft.

The Secondary Radar can provide （ ） information.

SSR code is a （ ） digital number.

Traffic information should include （ ） .

The phrase “Cleared via flight planned route” should not be used when granting a （ ） .

19KM is equal to （ ） .