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 9 to 13.

Scientists have experimented with a new procedure for alleviating the damage caused by strokes. Strokes are frequently caused by a blood clot lodging in the tree of arteries in the head, choking the flow of blood. Some brain cells die as a direct result of the stroke, but others also die over several hours because the proteins spilling out of the first cells that die trigger a chemical chain reaction that kills the neighboring cells.

The current method of reducing the amount of damage is to give a clot dissolver, known as TPA, as soon as possible. But generally TPA is not given to the patient until he or she reaches the hospital, and it still does not immediately stop the damage.

The new technology, still in the research stage, involves chilling the area or the entire patient. It is already known that when an organ is cooled, damage is slowed. This is why sometimes a person who has fallen into an icy pond is not significantly harmed after being warmed up again. The biggest issue is the method of cooling. It is not feasible to chill the head alone. Doctors have chilled the entire body by wrapping the patient in cold materials, but extreme shivering was a problem.

The new idea is to cool the patient from the inside out. Several companies are studying the use of cold-tipped catheters, inserted into the artery in the groin and threaded up to the inferior vena cava, which is a large vein that supplies blood to the abdomen. The catheter is expected to cool the blood that flows over it, thus allowing cooler blood to reach the area of the stroke damage.

It is not expected that the cooling will be substantial, but even a slight decrease in temperature is thought to be helpful. In effect, the patient is given a kind of forced hypothermia. And doctors believe it is important to keep the patient awake so that they can converse with the patient in order to ascertain mental condition.

Studies continue to determine the most effective and least damaging means of cooling the patient in order to reduce this damage.

What is the passage mainly about?

A. The dangers of cooling the body. 

B. New pharmaceutical methods for reducing stroke damage that are being researched. 

C. Causes and effects of strokes. 

D. A new method of cooling the body to reduce stroke damage that is being researched.

Trong các nhân tố tiến hoá sau đây, có bao nhiêu nhân tố có thể làm thay đổi tần số alen của quần thể?

I. Đột biến.

II. Chọn lọc tự nhiên.

III. Di - nhập gen.

IV. Giao phối không ngẫu nhiên.

V. Các yếu tố nhẫu nhiên.

A. 2.

B. 5.

C. 4.

D. 3.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

Home schooling is apparently very successful. Many people still believe in the benefits of traditional schooling.

A. Because home schooling is apparently very successful, many people still believe in the benefits of traditional schooling

B. As long as home schooling is apparently very successful, many people still believe in the benefits of traditional schooling

C. Even though home schooling is apparently very successful, many people still believe in the benefits of traditional schooling

D. In spite of home schooling is apparently very successful, many people still believe in the benefits of traditional schooling

Trong chọn giống, để tạo được giống có ưu thế lai cao, người ta làm theo quy trình:

       (1) cho lai giữa các dòng thuần chủng với nhau (lai khác dòng đơn, lai khác dòng kép; lai thuận nghịch; lai xa...

       (2) chọn tổ hợp lai có ưu thế lai cao.

       (3) Tạo dòng thuần chủng bằng cách cho tự thụ phấn hoặc giao phối cận huyết qua nhiều đời.

A. (3), (2), (1)

B. (1), (2), (3) 

C. (3), (1), (2) 

D. (2), (1), (3)

Có 3 tế bào sinh tinh của một cá thể có kiểu gen AaBbddEe tiến hành giảm phân bình thường hình thành tinh trùng. Số loại tinh trùng tối đa có thể tạo ra là

A. 2

B. 4

C. 8

D. 6

Theo IUPAC ankin CH₃-C ≡ C-CH­₂-CH₃ có tên gọi là

A. pent-2-in

B. etylmetylaxetilen

C. pent-1-in

D. pent-3-in

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.

If you enjoy water sports, Hawaii is the place for you. You can go swimming all year round in the warm water. You can go sport fishing from the shore or from a boat. If you like boats, you can go sailing, canoeing, or windsurfing. Or, you can also try some other water sports that are especially popular in Hawaii. surfing, snorkeling and scuba diving.

Surfing is a sport which started in Hawaii many years ago. The Hawaiians called it “he’e nalu”, which means “to slide on a wave”. If you want to try surfing, you need, first of all, to be a good swimmer. You also have to have an excellent sense of balance. You must swim out from the beach with your surfboard under your arm. When you get to where the waves begin to break, you wait for a calm moment. Then you try to stand up on the board. The wave will begin to rise under you. You must try to steer the board with your feet so you stay on top of the wave. The important thing is to keep your balance and not fall down. If you can manage this, you will have an exciting ride all the way in to the shore.

Scuba diving and snorkeling are two ways to get a close look at the beauty lying below the surface of the ocean. The waters off the Hawaiian Islands are clean, clear and warm. They contain hundreds of kinds of colorful fish. The undersea world is made even more colorful by the coral reefs of red, gold, white and light purple. Among these reefs there may be larger fish or sea turtles. Scuba diving allows you to see the most interesting undersea sights. “Scuba” means “Self-contained Underwater Breathing Apparatus”, that is, equipment for breathing and swimming around far under water. In Hawaii, you can take special courses to learn how to scuba dive. After the courses, you can get a certificate that will allow you to dive alone. Since it can be dangerous, proper instruction and great care are always necessary when you are scuba diving.

If you are adventurous, you might try snorkeling instead of scuba diving. Less equipment is needed, just a face mask, a breathing tube (snorkel) and flippers for your feet. It only takes a few minutes to learn how to snorkel. Although you cannot dive deep into the water, you can swim with your face below the surface. Breathing through the tube, you float on the surface, and keep yourself moving with your flippers. Even from the surface like this, there will be plenty of color and beauty to see.

The word “proper” in paragraph 4 refers to______________.

A. enthusiastic

B. informative

C. appropriate 

D. short and clear