一汽车质量为m，以恒定的功率从静止启动．汽车沿水平路面行驶S后，速度达到最大速度v，其后汽车做匀速运动．已知汽车所受阻力恒为车重的k倍，求汽车加速运动S的过程重所经历的时间t为多少．

B

    You may know the English letters A, B and C, but do you know there are people called "ABC"? You may like eating bananas, but do you know there are people called "banana persons"? If you don't know, I will tell you about it. They are some Chinese people like you and me, but they aren't in China. Why do people call them like that?

    If we call somebody an ABC person, we mean he or she is a Chinese but was born in America. Sometimes, people also call them "banana persons". A banana is yellow outside and white inside. So if somebody is a "banana person", he or she is "white" inside and "yellow" outside. By saying that, we mean he or she has yellow skin(皮肤) but does things in an American way. "Banana persons" were born in America and they live in America for a long time, so they think like Americans and do things like Americans. However, these people still have Chinese blood(血统). Their parents, grandparents or even great-grandparents are from China. They all have black eyes and black hair, so they look like us, Chinese people.

    There are many famous "banana persons" in America. They do very well in America and they are really great in their own fields.

巴拿马运河沟通了