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

The principle of use and disuse states that those parts of organisms' bodies that are used grown larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise  particular muscles, they grow. Those that are never used dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. Enthusiasts of the "body- building" cult make use of the principle of use and disuse to "build" their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer's hands are horny, hardened by long exposure to rough work. The teller's hands are relatively soft.

The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions.

Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency and rickets. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is "used", and fades to white when it is not.

What does the passage mainly discuss?

A. How the principles of use and disuse change people's concepts of themselves.

B. The way in which people change themselves to conform to fashion

C. The changes that occur according to the principle of use and disuse

D. The effects of the sun on the principle of use and disuse

Có bao nhiêu amin bậc một, có mạch cacbon phân nhánh là đồng phân cấu tạo của nhau ứng với công thức phân tử C₄H₁₁N

A. 4 

B. 1

C. 2 

D. 3 

I need time to think about   ________ offer you gave me.

A. a

B. an

C. the

D. –

Hỗn hợp X gồm peptit A mạch hở có công thức C_xH_yN₅O₆ và hợp chất B có công thức phân tử là C₄H₉NO₂.Lấy 0,09 mol X tác dụng vừa đủ với 0,21 mol NaOH chỉ thu được sản phẩm là dung dịch gồm ancol etylic và a mol muối của glyxin,b mol muối của alanin.Nếu đốt cháy hoàn toàn 41,325 gam hỗn hợp X bằng lượng oxi vừa đủ thì thu được N₂ và 96,975 gam hỗn hợp CO₂ và H₂O.Giá trị a:b gần nhất với:

A. 0,50.

B. 0,76.

C. 1,30.

D. 2,60.

The pioneer thinkers of the 18th century advocated that women should not be discriminated against ________ the basis of their sex.

A. on

B. in

C. to

D. at

X là tripeptit, Y là tetrapeptit và Z là hợp chất có CTPT là C₄H₉NO₄ (đều mạch hở). Cho 0,2 mol hỗn hợp E chứa X, Y, Z tác dụng hoàn toàn với dung dịch chứa 0,59 mol NaOH (vừa đủ). Sau phản ứng thu được 0,09 mol ancol đơn chức; dung dịch T chứa 3 muối (trong đó có muối của Ala và muối của một axit hữu cơ no, đơn chức, mạch hở) với tổng khổi lượng là 59,24 gam. Phần trăm khối lượng của X trong E là:

A. 16,45%

B. 17,08%

C. 32,16%

D. 25,32%

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.

      Perhaps better known than the Cullinan Diamond is the Hope Diamond, a valuable and blue gem with a background of more than 300 years as a world traveler.The 112-carat blue stone later became the Hope Diamond was mined in India sometime before the middle of the seventeenth century and was first known to be owned by Shah Jahan, who built the Taj Mahal in memory of his beloved wife. From India, the celebrated blue stone has changed hands often, moving from location to location in distant corners of the world.

      In the middle of the seventeenth century, a trader from France named Jean Baptiste Tavernier acquired the large blue diamond, which was rumored to have been illegally removed from a temple Tavemier returned to France with the big blue gem, where the stone was purchased by the Sun King Louis XIV. Louis XIV had it cut down from 112 to 67 carats to make its shape symmetrical and to maximize its sparkle. The newly cut diamond, still huge by any standards, was passed down through the royal family of France, until it arrived in the hands of Louis XVI and Marie Antoinette. During the French Revolution, Louis XVI and his wife met their fate on the guillotine in 1793, and the big blue diamond disappeared from public sight.

      The diamond somehow managed to get from France to England, where banker Henry Hope purchased it from a gem dealer early in the nineteenth century. The huge blue stone was cut into a 45.5-carat oval, and at this point it took on the name by which it is known today. The diamond stayed in the Hope family for around a century, when deep indebtedness brought on by a serious gambling habit on the part of one of Henry Hope's heirs forced the sale of the diamond.

          From England, the Hope Diamond may have made its way into the hands of the Sultan of Turkey; whatever route it took to get there, it eventually went on to the United States when American Evelyn Walsh McLean purchased it in 1911. Mrs. McLean certainly enjoyed showing the diamond off guests in her home were sometimes astounded to notice the huge stone embellishing the neck of Mrs. McLean’s Great Dane as the huge pet trotted around the grounds of her Washington, D.c. home. The Hope Diamond later became the property of jeweler Harry Winston, who presented the stunning 45.5- carat piece to the Smithsonian in 1958. The Hope Diamond is now taking a well-earned rest following its rigorous travel itinerary and is on display at the Smithsonian Institution in Washington, D.C., where it has been since 1958.

The pronoun "it" in the passage refers to

A. its shape

B. the newly cut diamond

C. the royal family

D. the French Revolution

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 45 to 54.

Although speech is the most advanced form of communication, there are many ways of communicating without using speech. Signals, signs, symbols, and gestures may be found in every known culture. The basic function of signal is to impinge upon the environment in such a way that it attracts attention, as, for example, the dots and dashes of a telegraph circuit. Coded to refer to speech, the potential for communication is very great. Less adaptable to the codification of words, signs also contain meaning in and of themselves. A stop sign or a barber pole conveys meaning quickly and conveniently.

Symbols are more difficult to describe than either signals or signs because of their intricate relationship with the receiver’s cultural perceptions. In some cultures, applauding in a theater provides performers  with an auditory symbol of approval. Gestures such as waving and handshaking also communicate certain cultural messages.

Although signals, signs, symbols, and gestures are very useful, they do have a major disadvantage in communication. They usually do not allow ideas to be shared without the sender being directly adjacent  to the receiver. Without an exchange of ideas, interaction comes to a halt. As a result, means of communication intended to be used for long distances and extended periods must be based upon speech. To radio, television, and the telephone, one must add fax, paging systems, electronic mail, and the Internet, and no one doubts but that there are more means of communication on the horizon.

The word “intricate” in paragraph 2 could best be   replaced by_________.

A. inefficient                  

B. complicated               

C. historical                   

D. uncertain

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 following questions.

The change in population distribution was barely noticeable to the demographers conducting the study.

A. often      

B. hardly     

C. never      

D. softly