《2025年全优方案组合训练九年级英语全一册人教版》

Have you ever wondered why big heavy airplanes can fly? Why do planes have to move so fast on a runway before they can take off?
When a plane moves into the wind,the wings cut the air in half. Some air travels above the wing,and some air travels below the wings as shown in the picture below.
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Plane wings are built to be curved(弧形的) on top and flat(扁平的) on the bottom. The wind,or airstream,flowing over the wings travels a different path from air traveling under the wings. This difference in the path of the wind,creates lower air pressure above the wings as shown in the picture. The higher air pressure under the wings lifts the plane into the air creating lift. When there is enough lift to overcome gravity,the plane takes off.
All the time,the plane is being slowed down by having to push through the air. This is called drag,and the engines have to overcome it. As long as the plane continues to move forward at a fast enough speed,the plane continues to fly.
Planes use engines to move quickly down the runway to create the lift for taking off. Helicopters(直升机) rotate(旋转) their wings(or blades). The rotating motion forces air past the wings to create lift.
(B)1. According to the passage,which of the following is NOT TRUE about plane wings?
A. Air below the wings travels slower than the air above the wings.
B. Plane wings are curved on both sides.
C. The air pressure under the wings is higher than that above the wings.
D. The winds flowing over or under the wings travel differently.
(C)2. The underlined word “gravity” in the passage probably means “______” in Chinese.
A. 拉力
B. 压力
C. 重力
D. 阻力
(A)3. To make the plane fly,what do the engines have to overcome?
A. Being slowed down while pushing through the air.
B. Not having a fast enough speed.
C. Higher air pressure above the wings.
D. There being too much lift.
(C)4. What’s the main purpose of the passage?
A. To show us in what way the plane flies in the sky.
B. To introduce us what plane wings look like.
C. To tell us how an airplane takes off and what makes it fly.
D. To give us some common knowledge of air pressure.

答案： 1. B【解析】细节理解题。根据第三段第一句可知，飞机机翼是弧形的，底部是平的。
2. C【解析】词义猜测题。由常识可知，当有足够的升力来克服重力时，飞机才能起飞，由此可猜测 gravity 的意思是“重力”。
3. A【解析】细节理解题。根据第四段前两句可知，第二句中的 it 指代的是第一句中的“being slowed down by having to push through the air”，由此可知答案为A。
4. C【解析】主旨大意题。文章第一段提出了两个问题，全文围绕这两个问题展开了说明：飞机通过什么原理起飞及飞行，故答案为C。