问题 单项选择题

公路桥涵设计的作用(或荷载)分类,以下______项正确

A.恒载、车辆荷载及其影响力、其他荷载和外力
B.永久作用、基本可变作用、偶然作用
C.永久作用、可变作用、偶然作用
D.恒载、汽车荷载、风力、地震力作用

答案

参考答案:C

解析:
公路桥涵设计采用的作用分为永久作用、可变作用和偶然作用三类。公路桥涵设计时,对不同的作用采用不同的代表值。永久作用应采用标准值作为代表值。可变作用应根据不同的极限状态分别采用标准值、频遇值或准永久值作为其代表值。承载能力极限状态设计及按弹性阶段计算结构强度时应采用标准值作为可变作用的代表值。正常使用极限状态按短期效应(频遇)组合设计时,应采用频遇值作为可变作用的代表值;按长期效应(准永久)组合设计时,应采用准永久值作为可变作用的代表值。偶然作用取其标准值作为代表值。作用的设计值规定为作用的标准值乘以相应的作用分项系数。

单项选择题
阅读理解

A 70-year study of personality suggests that pessimism is a risk factor for early death, especially among men.

  The study results also indicate that pessimism can be linked to increased risk for sudden death from accidents or violence, according to the report published in the March issue of Psychological Science.

  Christopher Peterson of the University of Michigan and his colleagues analyzed data from the Terman Life-Cycle Study, which began by studying California public-school children with high IQs in 1921 and followed them through their life. Most of the 1,528 children were teenagers when the study began. Those still living are now in their 80s. In 1936 and 1940, participants were asked to complete a questionnaire designed to obtain information about difficult life events and their effect on overall outlook. One such question was, “What do you regard as your most serious fault of personality or character?”

  Pessimists were defined as fatalistic(宿命论的)people who tend to blame themselves when things go wrong and who believe that one bad event can ruin the rest of their life. They also tend to expect bad things to happen to them and feel that they have little or no ability to change their situation.

  Males were more likely than females to be classified as pessimistic. Compared with individuals with a more cheerful and optimistic outlook, pessimists were more likely to die from accidents and violence (including suicide).

  A pessimistic personality may lead to poor problem-solving ability, social difficulties and risky decision-making. Taken together, these variables put the pessimist at higher risk of untimely(不适时的) death, say the researchers. Such a person is less likely to avoid or escape potentially dangerous situations, the researchers concluded. “A pessimistic way of thinking in which people worry too much about bad events, predicts untimely death decades later,” according to Peterson.

小题1:According to the passage, you may be a pessimistic person, if one failure makes you feel________.

A.other people have been unfair to you.

B.other people will help you.

C.you cannot change a bad situation.

D.you can do better next time.小题2:According to the passage, pessimists may feel all of the following EXCEPT________

A.helpless when faced with difficulties.

B.cheerful when faced with troubles.

C.hopeless when one bad event occurs.

D.guilty when things go wrong.小题3:Which of the following statements is true, according to the passage?

A.Pessimists believe that everything in life depends on fate.

B.There are more pessimists among women than among men.

C.Most pessimists will end up committing suicide.

D.All pessimists will eventually die from accidents.小题4:The Terman Life-Cycle Study is a research program that studies________.

A.people over 70 years old.

B.people since their childhood.

C.pessimistic people over 80 years old.

D.only younger people.小题5:The analysis made by Christopher Peterson and his colleagues shows that pessimistic people________

A.will die from violence if they learn to be optimistic.

B.will more likely die from violence than optimistic people.

C.will die from violence because their IQs are low.

D.will die untimely if they are not able to learn to be cheerful and optimistic.