基本自动相关监视报文包括的内容是（）。

Emergency frequency is （ ） .

“PAN” is the international RTF（ ） signal.

“MAYDAY” is the international RTF （ ） signal.

According to ICAO definition, a condition concerning the safety of an aircraft or other vehicle or of some person on board or within sight but which does not require immediate assistance is （ ） .

There are （ ） VHF channels provided for the aviation voice communications.

Which SSR Code is not right?

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.