东风11型内燃机车在主发电机励磁电路中设置电阻R4及R7？R9有何作用？

阅读理解。

     SOUTHPORT, ENGLAND-A British teaching union famous for strange ideas has supported proposal to

employ dogs as classroom assistants.

      At the annual conference of the Professional Association of teachers in Southport, northwest of England,

one person suggested properly trained dogs be able to keep order in primary schools. They can round up lost

children and protect those who experience unfortunate"accidents". Wendy Dyble, a Sheetland Islands woman

who teaches children up to age seven, made it clear to her fellow friends that she was not "barking mad". They

obviously believed her, supporting her idea by 16 votes to 13, with a total of 63 abstentions. 

     He said big dogs could help round up children, keep them in line, lick up the milk they spill on the floor and

provide the extra eyes that a teacher needs to keep order."A big dog would also be helpful for breaking up

fights and look for lost property, like gym shoes or dolls," Dyble said at the conference."The dog will also be

useful in sniffing out smells that children do not own up to," she added. "It would be nice for the teacher not to

have to go round sniffing each child to find the culprit."

     The idea was greeted by the Dog Defense League but less so by bigger teaching unions. A spokesman for

Education Secretary David Blunkett, who is blind, said his guide dog was always popular with pupils when he

visited schools. The Professional Association of Teachers, with around 35,000 members, is the smallest

teaching union in Britain. It has an honour for occasional strange ideas.

     Earlier this week, its annual conference here suggested stopping exams because they lead to stress and

introducing selection at the age of 12 based on physical coordination and manual skill in the use of hand.

1. According to the writer's opinion, to employ dogs as classroom assistants _____.

A. is a wonderful idea

B. can improve the relation between children and animals

C. is beyond ordinary people's minds

D. can make some teachers lose jobs

2. What Dyble said at the conference _____.

A. gained some support from the members

B. frightened everyone at the conference

C. interested everyone at the conference

D. caused some trouble to trained dogs

3. A spokesman for Education Secretary _____.

A. once used a dog as classroom assistant

B. sang high praise for Dyble's idea

C. would employ dogs as teachers

D. benefited from dogs more than others

4. The last paragraph of this passage _____.

A. has nothing to do with the topic of this passage

B. shows there are too many exams in British school

C. provides further facts about the teaching union

D. shows the writer's anger to the union

双端固定桥受近中向倾斜力时，有关基牙运动方式的错误说法是（）

A.基牙与邻牙的良好接触有助固位

B.两基牙近中倾斜移位时，力集中在基牙牙冠的近中边缘嵴上

C.桥体受力时，两基牙会以一支点为中心向近中倾斜移动

D.固位力较差一端的基牙固位体易松动脱落

E.固位良好时，牙周条件较差一端的基牙易受伤害

李斯之子李由最后投降了项羽。（）

初期发现的烟草像黄花烟草，统叫晒烟，俗称土烟。

目前，国内汽车行业采用阴极电泳涂装所占的比率为（）。

A.60%以上

B.70%以上

C.80%以上

D.90%以上