Air traffic controllers direct the movements of all planes on the ground and in the air by ______. A: touching different buttons in the planes. B: sending them signals in the directing tower with flags. C: drawing maps with pens and pencils. D: keeping track of them on large radar screens.
Air traffic controllers direct the movements of all planes on the ground and in the air by ______. A: touching different buttons in the planes. B: sending them signals in the directing tower with flags. C: drawing maps with pens and pencils. D: keeping track of them on large radar screens.
The terrorists Hijacked ( ) planes.
The terrorists Hijacked ( ) planes.
Has it been announced _____? A: when are the planes to take off B: that are the planes to take off C: where are the planes to take off D: when the planes are to take off
Has it been announced _____? A: when are the planes to take off B: that are the planes to take off C: where are the planes to take off D: when the planes are to take off
Planes take off and land there.
Planes take off and land there.
She flying on planes and travelling by train
She flying on planes and travelling by train
The planes have to undergo _____ safety checks.
The planes have to undergo _____ safety checks.
Which is not sent by the US military A: Amy B: Ships. C: Planes. D: Personnel.
Which is not sent by the US military A: Amy B: Ships. C: Planes. D: Personnel.
____________ the area from which planes take off at an airport.
____________ the area from which planes take off at an airport.
Two planes are flying ______ the city. A: in B: under C: above
Two planes are flying ______ the city. A: in B: under C: above
中国大学MOOC: We are becoming increasingly dependent on computers. They are used in businesses, hospitals, crime detection and even to fly planes.
中国大学MOOC: We are becoming increasingly dependent on computers. They are used in businesses, hospitals, crime detection and even to fly planes.