问题 单项选择题

现代新型超长行程柴油机为使其工作循环趋向等压加热,循环的主要措施之一是()。

A.增大喷油提前角

B.采用高增压

C.采用短连杆

D.大幅度提高压缩比

答案

参考答案:D

解析:当代船用大型低速超长行程柴油机为了提高经济性,采用的压缩比越来越大,使ε提高到16~19的高水平。当压缩比提高到一定程度时,其工作循环趋向于等压加热,可提高其热效率,进而提高柴油机的经济性。

单项选择题
阅读理解

When a 13-year-old Virginal girl started sneezing, her parents thought it was merely a cold. But when the sneezes continued for hours, they called in a doctor. Nearly two months later the girl was still sneezing, thousands of times a day, and her case had attracted worldwide attention.

Hundreds of suggestions, ranging from “put a clothes pin on her nose” to “have her stand on her head” poured in. But nothing did any good. Finally, she was taken to Johns Hopkins Hospital where Dr. Leo Kanner, one of the world’s top authorities on sneezing, solved the baffling (难以理解的) problem with great speed.

He used neither drugs nor surgery for, curiously enough, the clue for the treatment was found in an ancient superstition(迷信) about the amazing bodily reaction we call the sneeze. It was all in her mind, he said, a view which Aristotle, some 3,000 years earlier, would have agreed with heartily.

Dr. Kanner simply gave a modern psychological interpretation to the ancient belief that too much sneezing was an indication that the spirit was troubled; and he began to treat the girl accordingly.

“Less than two days in a hospital room, a plan for better scholastic and vocational(职业的) adjustment, and reassurance about her unreasonable fear of tuberculosis(肺结核) quickly changed her from a sneezer to an ex-sneezer,” he reported.

Sneezing has always been a subject of wonder, awe and puzzlement. Dr Kanner has collected thousands of superstitions concerning it. The most universal one is the custom of begging for the blessing of God when a person sneezes— a practice Dr. Kanner traces back to the ancient belief that a sneeze was an indication that the sneezer was possessed of an evil spirit. Strangely, people over the world still continue the custom with the traditional, “God bless you” or something else.

When scientists look at the sneeze, they see a remarkable mechanism(身体机制) which, without any conscious help from you, takes on a job that has to be done. When you need to sneeze you sneeze, this being nature’s clever way of getting rid of an annoying object from the nose. The object may be just some dust in the nose which nature is trying to remove.

51. The girl sneezed continuously because she __________.

A. was ill                                B. was mentally ill

C. had heavy mental burden                 D. had attracted world-wide attention

52. When the girl began to sneeze continuously, ___________.

A. a lot of people offered their advice

B. she was taken to John Hopkins Hospital

C. she was given a treatment found in ancient superstition

D. many doctors treated her in different ways

53. Dr. Kanner cured the girl by ___________.

A. using Aristole’s method                   B. giving her psychological treatment

C. practicing superstition                    D. treating her tuberculosis

54. When a person sneezes, we say “God bless you” because____________.

A. it’s a tradition                           B. the person is possessed of an evil spirit

C. the person is ill                          D. God will bless those who sneeze

55. According to scientists, people sneeze because _____________.

A. they are ill                              B. to sneeze is human nature

C. they do not need any conscious help         D. there are unwanted things in their noses