成年妇女子宫颈管的长度应为()A．1．0～2．0cm B．2．0～2．5cm C．2

Placing a human being behind the wheel of an automobile often has the same curious effect as cutting certain fibres in the brain.

The result in either case is more primitive behaviour. Hostile feelings are apt to be expressed in an aggressive way.

The same man who will step aside for a stranger at a doorway will, when behind the wheel, risk an accident trying to beat another motorist through an intersection. The importance of emotional factors in automobile accidents is gaining recognition. Doctors and other scientists have concluded that the highway death toll resembles an epidemic and should be investigated as such.

Dr. Ross A. McFarland, Associate Professor of Industrial Hygiene at the Harvard University School of Public Health, said that accidents “now constitute a greater threat to the safety of large segments of the population than diseases do. ”Accidents are the leading cause of death between the ages of 1 and 35. About one third of all accidental deaths and one seventh of all accidental injuries are caused by motor vehicles.

Based on the present rate of vehicle registration, unless the accident rate is cut in half, one of every 10 persons in the country will be killed or injured in a traffic accident in the next 15 years.

Research to find the underlying causes of accidents and to develop ways to detect drivers who are apt to cause them is being conducted at universities and medical centres. Here are some of their findings so far:A man drives as he lives. If he is often in trouble with collection agencies, the courts, and police, chances are he will have repeated automobile accidents. Accident repeaters usually are egocentric, exhibitionistic, resentful of authority, impulsive, and lacking in social responsibility. As group, they can be classified as borderline psychopathic personalities, according to Dr. McFarland.

The suspicion, however, that accident repeaters could be detected in advance by screening out persons with more hostile impulses is false. A study at the University of Colorado showed that there were just as many overly hostile persons among those who had no accidents as among those with repeated accidents.

Psychologists currently are studying Denver high school pupils to test the validity of this concept. They are making psychological evaluations of the pupils to see whether subsequent driving records will bear out their thesis.

Dr. McFarland emphasizes the great menace of accidents by comparing it to（）

A. psychopathic behaviour

B. an epidemic

C. hostile attitudes

D.antisocial behaviour

关于染色体、DNA、基因的关系叙述不正确的是（　　）

A．染色体上都有DNA，DNA上都有基因

B．DNA是染色体的组成成分，基因是DNA分子上的片段

C．每个染色体上都有许多的DNA分子，每个DNA分子上都有许多的基因

D．在生物的传种和接代的过程中，基因是随染色体而传递的

缺铁性贫血与铁粒幼细胞性贫血的鉴别要点是（）

A.血清铁饱和度

B.MCV、MCHMCHC测定

C.骨髓铁染色

D.红细胞内游离原卟啉测定

E.血清总铁结合力

数据结构分为逻辑结构和存储结构，循环队列属于（）结构。

泡沫灭火器、干粉灭火器、二氧化碳灭火器这种分类是按照（）划分的。

A、充装的灭火剂

B、加压方式

C、重量

D、移动方式