超星 - 词汇学习三 - 查题吧

单选题

Before the airplane begins to move, thrust must be _____.

A. exerted
B. reduced
C. increased
D. maintained

单选题

As long as the thrust continues to be greater than the drag, the airplane continues to _____.

A. decelerate
B. advance
C. move
D. accelerate

单选题

When drag equals thrust, the airplane flies at a _____ airspeed.

A. changeless
B. constant
C. same
D. fixed

单选题

Roughly, these ranges can be grouped in three categories: low-speed flight, _____ flight, and high-speed flight.

A. takeoff
B. landing
C. cruising
D. medium-speed

单选题

If thrust decreases and airspeed decreases, lift becomes less than weight and the airplane will start to _____.

A. descend
B. climb
C. stall
D. flare

单选题

Actually, the airplane could not continue to travel in level flight at a constant altitude and maintain the same angle of attack if the _____ is increased.

A. power
B. lift
C. thrust
D. velocity

单选题

This is normally accomplished by reducing the angle of attack, i.e., _____ the nose.

A. moving
B. raising
C. tipping
D. lowering

单选题

There is, of course, a limit to how far the angle of attack can be increased, if a _____ is to be avoided.

A. acceleration
B. stall
C. deceleration
D. failure

单选题

Lift and drag also vary directly with the _____ of the air.

A. concentration
B. density
C. intensity
D. condition

单选题

Warm air is less dense than cool air, and _____ air is less dense than dry air.

A. humid
B. wet
C. moist
D. damp

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