单项选择题

It is delight to fly at the Pole because there _______.

A．planes fly higher than at the equator
B．the eyes can reach about 4,000 meters
C．planes are clear of bad weather
D．planes fly more quickly than at the equator

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热门试题

单项选择题

Airplanes usually do not need to climb quickly or fly high in the polar region because _______.

A．they do not land them
B．there are not clouds at all
C．they can cross the ice with special equipment
D．it is very cold

单项选择题

Airplanes can climb quickly _______.

A．in warm air
B．in cold air
C．when it reaches the polar region
D．only when the clouds are down low