According to the passage, why do people jo

I'm afraid _  _    in the river and my brother   is afraid of _       , too.    [ ]

A. to swim; swimming  

B. swim; swim  

C. swimming; swimming  

D. to swim; to swim

客车转向架的构架因各弹簧支柱安装平面的平面度超限（）。

A、不会引起行车事故

B、会造成车辆振动很大

C、主要会增大支柱套的磨损

D、易产生行车燃轴

三相桥式整流电路中的整流元件所承受的反向电压等于电源线电压的（）。

A.平均值

B.峰值

C.有效值

The following is a text about the perpetual motion machine. In the paragraphs with numbers, the supporting details, data or facts have been omitted and are listed following the text in random order. Match each of the details with the statement it supports.
Perpetual Motion Machine is a fascinating and long-discussed topic that moves well beyond the scope of physics. In short, a perpetual motion machine can be likened to a magic cow that continues to live and breathe and yet needs no sustenance. A perpetual motion engine installed in a car would continue to run indefinitely but would need neither gas tank nor petrol. Of course, as a perpetual motion machine is in violation of natural laws, it will likely never move out of the realm of imagination and into reality. When the phrase " perpetual motion machine " is entered into Google’s search engine, 34,400 items are returned. Of these 34,400 items, the forty-first to the forty-fifth hold reasonable interest and will be further discussed herein.
41. Myths and legends
Long before the advent of the steam engine, human beings have ruminated on the possibility of a perpetual motion machine. Throughout history, many have attempted to invent such a device, though none have thus far been successful.
42. Fame and glory
Some people hold that any inventor attempting to create a perpetual motion machine must only be in it for credit and accolades, wishing to be the first in his field to discover the much-coveted secret.
43. Wealth and riches
It is also suspected by some that those seeking to unlock the mystery of perpetual motion machine must be motivated by the monetary rewards. If such a device were to fall into popular use, the inventor would be a wealthy man indeed.
44. Antics and capers
Even some of those who are aware of the impossibility of perpetual motion machine have invented something similar under the guise of perpetual motion machine in order to tease us.
45. Deception and trickery
Some people, though fully aware that they are incapable of inventing a perpetual motion machine, persist in arguing that they can with the intention of scamming us.
Though the perpetual motion machine is a dream long-sought after by the scientific community, it is improbable that it will ever be realized. We can, however, pour our resources into researching more practical energy conserving forms of power such as geothermal, hydro-electric, and solar power solutions.
[A] Inventor K declared, " The experiments with perpetual motion are on the verge of success. My products will soon be distributed throughout the world and used in a wide range of industrial applications. When that happens, my company will expand exponentially. I’ll make a fortune! "
[B] Inventor F told me excitedly, " Some complex details are currently under discussion to unearth the key to perpetual motion. If my experiment proves to be effectual, I will become a Nobel Prize winner. You know, the ceremony is held annually in Sweden and is broadcasted live to every corner of the globe. " It is no great wonder that Inventor F espoused enthusiasm. A functional perpetual motion machine is a wonder that would be marveled at for generations to come.
[C] In ancient China there was an extremely adroit man by the name of Zhu Geliang. It is said that he constructed a wooden horse which could walk unaided and could be used in the transportation of military supplies. As no records of this occurrence have been found, this tale has passed into legend.
[D] One of the closest things to a perpetual motion engine was the one installed on the Traveler 1 spacecraft, the first spaceship in human history to fly beyond the edges of our solar system. Though Traveler’s engine is able to Fun without maintenance for many years, it still requires energy—nuclear energy. So, strictly speaking, Traveler 1 does not run on a perpetual motion engine, but in fact needs energy as do all other machines.
[E] Mr, Goofy announced that he had effectively diagrammed the first perpetual motion machine. When a private corporate party purchased the patent, they found to their dismay that manufacturing it according to the design layout was technically infeasible. Furious, they sued Mr. Goofy for fraud, but even in the courtroom, Mr. Goofy would not be shamed. He simply retorted, " I’m just joking around. "
[F] Tom, proudly proclaiming that he had invented a clock that ran on perpetual motion, and had it placed in the central square of his town. The clock, he said, would work perfectly despite a lack of springs in the internal mechanism. A scientist later ascertained the secret and revealed it to the townspeople: the clock had been cleverly devised to run on temperature differentials.