在长方体ABCD-A1B1C1D1中,AA1=AD=2AB,若E,F分别为线段A

题型:填空题

问题:

在长方体ABCD-A1B1C1D1中,AA1=AD=2AB,若E,F分别为线段A1D1,CC1的中点,则直线EF与平面ABB1A1所成角的余弦值为_______.

考点:直线与平面所成的角
题型:填空题

C

Some experts feel that cars are certain to fall into disuse. They see a day in the not-too-distant future when all cars will be deserted and made useless. Other experts, however, think the car is here to stay. They hold that the car will remain a leading means of city travel in the foreseeable future.

The car will undoubtedly change greatly over the next 30 years. It should become smaller, safer, and more practical, and should not be powered by the gas engine. The car of the future should be far more pollution-free than present types.

Unless changes take place in the power system, the car in the future will still be the main problem in city traffic jams. One suggested solution to this essential problem is the automated (自动的) system, which seems to hold water.

When the car enters the highway system, a small arm will drop from the car and connect with a rail, which is similar to those powering subway trains electrically. Once joined to the rail, the car will become electrically powered from the system, and control of the car will pass to a central computer. The computer will then monitor all the car’s movements. The driver will use the telephone to dial instructions about his position and the place he heads for into the system. The computer will find the best way and reserve space for the car all the way to the correct exit from the highway. The driver will be free to relax and wait for the call that will warm him of his coming exit. It is believed that an automated highway will be able to deal with 10,000 cars per hour, compared with the 1,500 to 2,000 cars that can be carried by a present-day highway.

48. What is the main concern of the author of the passage?

A. How to make cars pollution-free.            B. How to make cars smaller and safer.

C. How to solve the problem of train jam.   D. How to develop an automated subway system.

49. We can infer from this passage that __________.

A. the car connected to the rail on the highway will be powered by electricity.

B. The lack of oil is forcing people to find new means to power automobiles.

C. The driver under the system will be told where to get out of the highway.

D. The future car will become larger, faster, prettier and less expensive.

50. What provides cars with electric power in an automated highway system?

A. An engine.        B.A rail.   C. A computer controller.            D. A small arm.

51. Which of the following statements is true according to the passage?

A. The driver puts his information in the system by email.

B. The new system can deal with 10 times as many cars as the present one.

C. After entering the automated system, the driver needs to do nothing but relax.

D. Some experts are not confident of the future, while the view of the author is hopeful.

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抗拉强度是通过()实验来测定的。

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某基层人民法院在审理一起侵权纠纷案件时,在判决书中漏写了诉讼费用。现判决书已经向双方当事人送达。在此情况下,该人民法院如何纠正这一失误( )

A.以通知书的形式告知双方当事人原判决书中的失误

B.以决定书的形式纠正原判决书的失误

C.以裁定书的形式纠正原判决书的失误

D.重新制作一份判决书,再次向双方当事人送达并收回原判决书

题型:填空题

行政主体所为的( )是内部行政行为。

A.行政许可

B.行政处分

C.行政复议

D.行政处罚

题型:填空题

[8]

A.②—①—③—④

B.②—④—①—③

C.①—③—④—②

D.④—①—③—②

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