An có 24 viên kẹo, Việt có 18 viên kẹo, Lan có 7 viên kẹo. Hỏi số kẹo của An và Việt gấp mấy lần số kẹo của Lan?

Yếu tố “thanh” trong từ nào dưới đây không đồng nghĩa với các từ còn lại?

A. Thanh đạm

B. Thanh bần  

C. Thanh thiên

D. Thanh cao

Người ta tổng hợp một mARN từ một hỗn hợp nuclêôtít có tỉ lệ A: U: G: X = 4: 3: 2: 1. Nếu sự kết hợp trong quá trình tổng hợp là ngẫu nhiên thì tỷ lệ bộ ba mã có chứa nuclêôtít A là:

A. 65,8% 

B. 52,6% 

C. 72,6% 

D. 78,4%

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.

      In the mid - nineteenth century, the United States had tremendous natural resources that could be exploited in order to develop heavy industry. Most of the raw materials that are valuable in the manufacture of machinery, transportation facilities, and consumer goods lay ready to be worked into wealth. Iron, coal, and oil - the basic ingredients of industrial growth - were plentiful and needed only the application of technical expertise, organizational skill, and labor.

      One crucial development in this movement toward industrialization was the growth of the railroads. The railway network expanded rapidly until the railroad map of the United States looked like a spider’s web, with the Steel filaments connecting all important sources of raw materials, their places of manufacture, and their centers of distribution. The railroads contributed to the industrial growth not only by connecting these major centers, but also by themselves consuming enormous amounts of fuel, iron, and coal.

      Many factors influenced emerging modes of production. For example, machine tools, the tools used to make goods, were steadily improved in the latter part of the nineteenth century - always with an eye to speedier production and lower unit costs. The products of the factories were rapidly absorbed by the growing cities that sheltered the workers and the distributors. The increased urban population was nourished by the increased farm production that, in turn, was made more productive by the use of the new farm machinery. American agricultural production kept up with the urban demand and still had surpluses for sale to the industrial centers of Europe.

          The labor that ran the factories and built the railways was recruited in part from American farm areas where people were being displaced by farm machinery, in part from Asia, and in part from Europe. Europe now began to send tides of immigrants from eastern and southern Europe - most of whom were originally poor farmers but who settled in American industrial cities. The money to finance this tremendous expansion of the American economy still came from European financiers for the most part, but the American were approaching the day when their expansion could be financed in their own “ money market”.

The word “ themselves” in the paragraph 2 refers to ________

A. sources  

B. centers   

C. railroads         

D. places

Mark the letter A, B, C, or D on your answer sheet to indicate the word or phrase that is CLOSEST in meaning to the underlined part in each of the followings.

Humans depend on species diversity to provide food, clean air and water, and fertile soil for agriculture

A. destruction

B. Contamination

C. fertilizer

D. variety

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 42.

(1) The ocean bottom - a region nearly 2.5 times greater than the total land area of the Earth - is a vast frontier that even today is largely unexplored and uncharted. Until about a century ago, the deepocean floor was completely inaccessible, hidden beneath waters averaging over 3,600 meters deep. Totally without light and subjected to intense pressures hundreds of times greater than at the Earth's surface, the deep-ocean bottom is a hostile environment to humans, in some ways as forbidding and remote as the void of outer space.

(2) Although researchers have taken samples of deep-ocean rocks and sediments for over a century, the first detailed global investigation of the ocean bottom did not actually start until 1968, with the beginning of the National Science Foundation's Deep Sea Drilling Project (DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP's drill ship, the Glomar Challenger, was able to maintain a steady position on the ocean's surface and drill in very deep waters, extracting samples of sediments and rock from the ocean floor.

(3) The Glomar Challenger completed 96 voyages in a 15-year research program that ended in November 1983. During this time, the vessel logged 600,000 kilometers and took almost 20,000 core samples of seabed sediments and rocks at 624 drilling sites around the world. The Glomar Challenger's core samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago and to calculate what it will probably look like millions of years in the future. Today, largely on the strength of evidence gathered during the Glomar Challenger's voyages, nearly all earth scientists agree on the theories of plate tectonics and continental drift that explain many of the geological processes that shape the Earth.

(4) The cores of sediment drilled by the Glomar Challenger have also yielded information critical to understanding the world's past climates. Deep-ocean sediments provide a climatic record stretching back hundreds of millions of years, because they are largely isolated from the mechanical erosion and the intense chemical and biological activity that rapidly destroy much land-based evidence of past climates. This record has already provided insights into the patterns and causes of past climatic change - information that may be used to predict future climates. 

The author refers to the ocean bottom as a "frontier" because it______.

A. is not a popular area for scientific research

B. contains a wide variety of life forms 

C. attracts courageous explorers

D. is an unknown territory