Cho tứ diện OABC có OA, OB, OC đôi một vuông góc với

nhau và OA = a, OB = 2a, OC = 3a. Thể tích của khối tứ

diện OABC bằng

A. V =  2 a 3 3

B. V =  a 3 3

C. V =  2 a 3

D. V =  a 3

Read the following passage  and  mark  the letter  A, B, C or D on your  answer  sheet to indicate  the correct  answer  to each of the following questions  from 39 to 40.

Animation traditionally is done by hand-drawing or painting successive frames of an object, each slightly different than the preceding frame. In computer animation, although the computer may be the one to draw the different frames, in most cases the artist will draw the beginning and ending frames and the computer will produce the drawings between the first and the last drawing. This is generally referred to as computer-assisted animation, because the computer is more of a helper than an originator.

In full computer animation, complex mathematical formulas are used to produce the final sequence of pictures. These formulas operate on extensive databases of numbers that define the objects in the pictures as they exist in mathematical space. The database consists of endpoints, and color and intensity information. Highly trained professionals are needed to produce such effects because animation that obtains high degrees of realism involves computer techniques for three-dimensional transformation, shading, and curvatures.

High-tech computer animation for film involves very expensive computer systems along with special color terminals or frame buffers. The frame buffer is nothing more than a giant image memory for viewing a single frame. It temporarily holds the image for display on the screen.

A camera can be used to film directly from the computer's display screen, but for the highest quality images possible, expensive film recorders are used. The computer computes the positions and colors for the figures in the picture, and sends this information to the recorder, which captures it on film. Sometimes, however, the images are stored on a large magnetic disk before being sent to the recorder. Once this process is completed, it is repeated for the next frame. When the entire sequence has been recorded on the film, the film must be developed before the animation can be viewed. If the entire sequence does not seem right, the motions must be corrected, recomputed, redisplayed, and rerecorded. This approach can be very expensive and time consuming. Often, computer-animation companies first do motion tests with simple computer-generated line drawings before selling their computers to the task of calculating the high-resolution, realistic-looking images

Which of the following statements is supported by the passage?

A. Computers have reduced the costs of animation.

B. In the future, traditional artists will no longer be needed.

C. Artists are unable to produce drawings as high in quality as computer drawings.

D. Animation involves a wide range of technical and artistic skills.

Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.

We bought some __________ 

A. old lovely German glasses

B. German old lovely glasses

C. German lovely old glasses

D. lovely old German glasses

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 28 to 34.

FAMILY LIFE IN THE UNITED STATES

Family life in the United States is changing. Fifty or sixty years ago, the wife was called a “housewife”. She cleaned, cooked, and cared for the children. The husband earned the money for the family. He was usually out working all day. He came home tired in the evening, so he did not do much housework. And he did not see the children very much, except on weekends.

These days, however, more and more women work outside the home. They cannot stay with the children all day. They, too, come home tired in the evening. They do not want to spend the evening cooking dinner and cleaning up. They do not have time to clean the house and do the laundry. So who is going to do the housework now? Who is going to take care of the children?

Many families solve the problem of housework by sharing it. In these families, the husband and wife agree to do different jobs around the house, or they take turns doing each job. For example, the husband always cooks dinner and the wife always does the laundry. Or the wife cooks dinner on some nights and the husband cooks dinner on other nights.

Then there is the question of the children. In the past, many families got help with child care from grandparents. Now families usually do not live near their relatives. The grandparents are often too far away to help in a regular way. More often, parents have to pay for child care help. The help may be a babysitter or a day-care center. The problem with t his kind of help is the high cost. It is possible only for couples with jobs that pay well.

Parents may get another kind of help form the companies they work for. Many companies now let people with children work part-time. That way, parents can spend more time with their children. Some husbands may even stop working for a while to stay with the children. For these men there is a new word. they are called “househusbands”. In the USA more and more men are becoming househusbands every year.

These changes in the home mean changes in the family. Fathers can learn to understand their children better, and the children can get to know their fathers better. Husbands and wives may also find changes in their marriage. They, too, may have a better understanding of each other.

The word “they” in paragraph 5 refers to ______.

A. husbands who stop working to stay with the children

B. fathers who spend more time with their children

C. parents who work part-time 

D. children who spend more time with fathers than

Though I didn't want my son to leave home since he was twenty-one, there was nothing I could do to ____ it

A. hinder

B. resist

C. prevent

D. cease

Mark the letter A, B, C or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.

A. sculpture

B. result

C. justice

D. figure

Hỗn hợp E gồm hai este là đồng phân cấu tạo. Đốt cháy hoàn toàn 33,3 gam E, thu được 30,24 lít khí CO₂ (đktc) và 24,3 gam H₂O. Đun nóng 33,3 gam E với 300 mL dung dịch NaOH 2M đến phản ứng hoàn toàn; cô cạn dung dịch sau phản ứng, thu được 38,7 gam chất rắn khan T. Đốt cháy toàn bộ T bằng khí O₂ dư, thu số mol CO₂ và số mol H₂O theo tỉ lệ số mol tương ứng là

A. 1 : 1

B. 2 : 1

C. 2 : 3

D. 3 : 4

Alex managed to put …………….his point of view very successfully in meetings.

A. up

B. in

C. across

D. on