题目内容：

    Flying is a fast way to travel. But it is a big headache for some people. They can’t help worrying about things like “Is it dangerous if we don’t change our mobile phones to airplane mode(飞行模式)? ”Here are some interesting facts about flying.

Why are plane windows round?

It’s for safety. As the airplane flies higher and higher, the atmospheric pressure(气压)outside gets lower and lower. During the flight, the pressure inside the plane becomes greater than the pressure outside.

When this happens, square windows can break. That’s because having different pressures inside and outside puts stress on the corners of square windows. But rounded corners can spread the pressure more evenly(均匀地)across the window’s surface(表面)，making it less likely to break.

What happens when a phone isn’t in airplane mode? 

Some passengers believe mobile phones and tablets need to be turned off  because they can bring the plane down. However, this is not true.

If you don’t change your phone to airplane mode, plots and air traffic controllers may hear unpleasant sounds in their headphones. This makes it harder for them to communicate. So it’s still best to put your devices(设备) in airplane mode.

Facts about flying
Round windows	It’s for 1. . As the airplane flies higher ,the pressure2.the plane is greater than the pressure3. When this happens, square windows can 4.while round windows spread the pressure more evenly5.the window’s surface.
Phones in airplane mode	Some people believe that their plane will crash if they don’t 6.their devices off. It’s not7.. Keep your phone on while flying will make unpleasant 8. in pilots’ and air traffic controllers’ 9..This makes it harder for them to10. .