在图中,线圈M和线圈P绕在同一铁芯上,则( ) A.当合上开关S的一瞬时,线圈P

题型:选择题

问题:

在图中,线圈M和线圈P绕在同一铁芯上,则(   )

A.当合上开关S的一瞬时,线圈P里没有感应电流

B.当断开开关S的一瞬时,线圈P里没有感应电流

C.当合上开关S的一瞬时,线圈P里有感应电流

D.当断开开关S的一瞬时,线圈P里有无感应电流无法判断

考点:互感现象
题型:选择题

药物在血液与组织间可逆性转运过程是

A.吸收
B.分布
C.代谢
D.排泄
E.转运

题型:选择题

Today I __________ fun.[ ]

A. have   

B. had    

C. has   

D. am going to have 

题型:选择题

There can be no doubt that the computer revolution has touched virtually every person in the country in some way or other.

Nor can there be any doubt that it has brought tremendous improvements in productivity and efficiency. 46) Indeed, there are many tasks undertaken by computers that could not be done without them, and we have reached the point that the benefits of computerization are taken for granted.

Having accepted that computers are here to stay, what is the downside 47) The most obvious answer is that because of increased efficiency, less people are needed and the loss of jobs, particularly in the service industries, has been enormous, with more .job losses yet to come.

However, on a more insidious note, many users have not realized how computers have introduced vulnerability to their business. If computers are soon a boon, how do we cope when something goes wrong

Computers have many uses, varying from pure accounting or back-office systems to stock or production control, or computer-aided design or manufacturing. 48) In many instances, manual systems can quickly be introduced to ensure some continuity of the business; but in many cases if the computer is down, so is the business.

The most probable causes of interruption in the past have been accidental damage or breakdown, and these can usually be dealt with expeditiously. However, in recent times the exposure causing most concern to insurers have been theft.

49) Initially the problem was the theft of PCs, and because most of these were based in offices which had not been targeted by thieves in the pasty and thus had relatively poor security, losses mounted very quickly. It was common practice for a thief to make a fresh visit once the equipment had been replaced, as the new equipment would be more attractive due to rapid technological advances. The equipment would usually be covered by insurance, but problems could be experienced if there were no back-ups of date and/or programmes.

The initial reaction by insurers was to step up requests for security improvements, including alarms and devices such as lock-down plates or cables. 50) However, the criminal fraternity quickly came to realize that the real value in the computers is in the chip which is remarkably portable and unidentifiable, so even when caught the police have trouble proving the theft. This led to even greater demands for security, including encapsulation and computer safes.

Indeed, there are many tasks undertaken by computers that could not be done without them, and we have reached the point that the benefits of computerization are taken for granted.

题型:选择题

急性扁桃体炎涂片检查出病原体多为()

A.阴性或一般细菌

B.喉杆菌

C.梭形杆菌及樊尚螺旋菌

D.链球菌

E.肺炎球菌

题型:选择题

轴的结构应该便于加工和尽量减少();而且对轴上零件要便于()和()。

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