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 38 to 45.

A rather surprisingly geographical feature of Antarctica is that a huge freshwater lake, one of the world's largest and deepest, lies hidden there under four kilometers of ice. Now known as Lake Vostok, this huge body of water is located under the ice block that comprises Antarctica. The lake is able to exist in its unfrozen state beneath this block of ice because its waters are warmed by geothermal heat from the earth's core. The thick glacier above Lake Vostok actually insulates it from the frigid temperature (the lowest ever recorded on Earth) on the surface.

The lake was first discovered in the 1970s while a research team was conducting an aerial survey of the area. Radio waves from the survey equipment penetrated the ice and revealed a body of water of indeterminate size. It was not until much more recently that data collected by satellite made scientist aware of the tremendous size of the lake; satellite -borne radar detected an extremely flat region where the ice remains level because it is floating on the water of the lake.

The discovery of such a huge freshwater lake trapped under Antarctic is of interest to the scientific community because of potential that the lake contains ancient microbes that have survived for thousands upon thousands of years, unaffected by factors such as nuclear fallout and elevated ultraviolet light that have affected organisms in more exposed areas. The downside of the discovery, however, lies in the difficulty of conducting research on the lake in such a harsh climate and in the problems associated with obtaining uncontaminated samples from the lake without actually exposing the lake to contamination. Scientists are looking for possible ways to accomplish this.

The passage mentions which of the following as a reason for the importance of Lake Vostok?

A. It may contain uncontaminated microbes

B. It can be studied using radio waves

C. It has already been contaminated.

D. It may have elevated levels of ultraviolet light.

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.

For more than six million American children, coming home after school means coming back to an empty house. Some deal with the situation by watching TV. Some may hide. But all of them have something in common. They spend part of each day alone. They are called “latchkey children”. They are children who look after themselves while their parents work. And their bad condition has become a subject of concern.

Lynette Long was once the principal of an elementary school. She said, “we had a school rule against wearing jewelry. A lot of kids had chains around their necks with keys attached. I was constantly telling them to put the keys inside shirts. There were so many keys; it never came to my mind what they meant.” Slowly, she learned that they were house keys. She and her husband began talking to the children who had keys. They learned of the effect working couples and single parents were having on their children. Fear wasthe biggest problem faced by children at home alone. One in three latchkey children the Longs talked to reported being frightened. Many had nightmares and were worried about their own safety. The most common way latchkey children deal with their fears is by hiding. They may hide in a shower stall, under a bed or in a closet. The second is TV. They often turn the volume up. It’s hard to get statistics on latchkey children, the Longs have learned. Most parents are slow to admit that they leave their children alone.

Question 43. The phrase “they” means

A. latchkey children’s parents

B. empty houses

C. latcthey children

D. all American children

He (learn)............................. English since he was ten years old.

cho hình vuông ABCD, M là trung điểm của cạnh AB, P là giao điểm của ai tia CM và DA

a) chứng minh tứ giác APBC là hình bình hành và tứ giác BCDP là hình thang vuông

b) Chứng minh 2S_BCDP=3S_APBC

c) gọi N là trung điểm của BC, Q là giao điểm của DN và CM.

Chứng minh AQ=QB.