Task 1
Directions: After reading the following passage, you will find 5 questions or unfinished statements, numbered 36 through 40. For each question or statement there are 4 choices marked A, B, C, and D. You should make the correct choice.
The Earth has a force that pulls things toward itself. We call this force gravity(地心引力). This is something we live with all the time, and we take it for granted and hardly ever think about it. But it is a most important factor in rocket operation and must be overcome if we are to get anywhere in space, or off the ground at all.
Take the throwing of a ball as an example. The harder the ball is thrown, the faster and higher it will go. What is the secret? It's speed. If we could throw the ball hard enough it would go up and up forever and never come down. The speed at which it would have to be thrown to do this is known as escape speed. Of course, we cannot throw a ball hard enough because the speed required to escape completely from' the Earth's gravity is seven miles per second, or over twenty-five thousand miles per hour.
Once escape speed has been reached by a spacecraft(宇宙飞船), no further power is needed. A rocket aimed at the Moon, for instance, will "coast"(滑行) the rest of the way because the Earth's gravity cannot then pull it back, and there is no air resistance(阻力) in space to slow it down. This "coasting" is known as "free fall". That does not mean the rocket is falling down towards the Earth but that it is traveling freely in space without the aid of power, like a bicycle coasting downhill.
Free fall is an important feature of space travel: it would be impossible to carry enough fuel to provide powered flight all the time.
What is the most important factor for a rocket to escape from the Earth?
A.To travel as fast as it can.
B.To overcome the Earth gravity.
C.To get away from the air resistance.
D.To have strong power in its operation.
第1题
A.没有在BIOS中设置为从SCSI设备引导
B.SCSI接口故障
C.其中的一个设备坏了
D.SCSIID设置错误
第5题
A.SCSI包括SCSI控制器和SCSI设备
B.SCSI控制器也称做主机适配器
C.SCIS控制器位于SCSI设备中
D.SCIS控制器作为插卡或一个电路单元而位于主板处
第8题
A.外部设备使用BERG连接器,而内部设备使用A或B类线缆连接器
B.外部设备使用7以上的SCSIID号,而内部设备使用的SCSIID号在0~7之间
C.外部设备需要外接电源支持,而内部设备使用计算机本身的电源供电
D.外部设备必须手动进行配置,而内部设备可以通过系统的PnP程序自动配置
为了保护您的账号安全,请在“上学吧”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!