当把射频信号施加到天线输入端时，天线便能有效地把射频信号所包含的电磁能量辐射到空中去，在天线附近的空间中形成（）。

The airborne equipment to match NDB is （ ） .

All radar identification techniques depend on （ ） .

Airborne SSR transponder is in fact a （ ） .

The SSR, system requires the use of three additional components to the basic radar equipment, they are （ ） .

Aircraft are required to comply with ATC instructions within （ ） .

If an aircraft performs the initial part of a flight as a controlled flight, and at a later stage will continue as an uncontrolled flight, the clearance limit should normally be （ ） .

An ATC unit addressed by an urgency call should （ ） .

Should the pilot of an aircraft equipped with a transponder experience a loss of two-way radio capability, he can be expected to （ ） .

When the inbound leg of an assigned holding pattern lies on the 030 radial of VOR，which holding direction will be specified in the clearance?

ACC may, after contact with approach, clear the first aircraft in an approach sequence for approach, otherwise, the aircraft should （ ） .