【正确答案】 D

【答案解析】[听力原文]19-22
We cannot feel speed. But our senses let us know that we are moving. We see things moving past us and feel that we are being shaken. We can feel acceleration, an increase in speed. But we notice it for only a short time. For instance, we feel it during the take-off run of an airplane. We feel the plane's acceleration, because our bodies do not gain speed as fast as the plane does. It seems that something is pushing us back against the seat. Actually, our bodies are trying to stay in the same place, while the plane is carrying us forward.
Soon the plane reaches a steady speed. Then, because there is no longer any change in the speed, the feeling of forward motion stops.

[精解] 题干问：“你如何解释我们是正在运动的?”听力材料中说“We cannot feel speed．But our senses let us know that we are moving. We see things moving past us and feel that we are being shaken．”即，我们可以通过观察周围物体的运动和感觉我们自己的颤动来知道我们正在运动。所以本题的答案选D。

【正确答案】 B

【答案解析】[精解] 题干问：“飞机起飞的时候，我们感觉怎么样?”听力材料中说：“It seems that something is pushing us back against the seat．”这和答案B的意思一致，所以本题答案选B。

【正确答案】 C

【答案解析】[精解] 题干问：“我们为什么能感觉到飞机的加速?”从听力材料“We feel the plane's acceleration，because our bodies do not gain speed as fast as the plane does．”可知，答案选C。

【正确答案】 C

【答案解析】[精解] 题干问：“什么时候能感觉到向前运动停止了?”对话材料最后说：“Soon the plane reaches a steady speed．Then，because there is no longer any change in speed，the feeling of forward motion stops．”该句的意思与答案C的意思一致。