Khi Mĩ thành lập Khối quân sự Bắc Đại Tây Dương (NATO), Liên Xô và các nước Đông Âu thành lập Tổ chức Hiệp ước Vácsava, những sự kiện đó đánh dấu

A. sự khởi đầu tình trạng Chiến tranh lạnh.

B. sự khởi đầu cho Chiến lược toàn cầu.

C. Chiến tranh lạnh đã bao trùm cả thế giới.

D. sự khởi đầu cho cuộc chạy đua vũ trang Xô - Mĩ.

Sự hình thành thạch nhũ trong các hang động đá vôi là nhờ phản ứng hoá học nào sau đây?

A. CaCO 3 + CO 2 + H 2 O → Ca ( HCO ₃ ) 2

B.  Ca ( OH ) 2 + Na 2 CO 3 → Ca CO 3 + 2 NaOH

C.  CaCO 3 → t 0 CaO + CO 2

D.  Ca ( HCO 3 ) 2 → CaCO 3 + CO 2 + H 2 O

Một tế bào sinh tinh trùng chứa các gen trên 2 cặp NST có kiểu gen Aa DE//de. Thực tế khi giảm phân bình thường có thể tạo nên số loại giao tử là:

A. 2 loại 

B. 4 loại 

C. 8 loại 

D. 2 loại hoặc 4 loại 

Read the passage and choose the best option for each sentence

In the United States, presidential elections are held in years evenly divisible by four (1888, 1900, 1964, etc.). Since 1840, American presidents elected in years ending with zero have died in office, with one exception. William H. Harrison, the man who served the shortest term, died of pneumonia only several weeks after his inauguration.

Abraham Lincoln was one of four presidents who were assassinated. He was elected in 1860, and his untimely death came just five years later. James A. Garfield, a former Union army general from Ohio, was shot during his first year in office (1881) by a man to whom he wouldn't give a job. While in his second term of office (1901), William McKinley, another Ohioan, attended the Pan-American Exposition in Buffalo, New York. During the reception, he was assassinated while shaking hands with some of the guests. John F. Kennedy was assassinated in 1963 in Dallas only three years after his election.

Three years after his election in 1920, Warren G, Harding died in office. Although it was never proved, many believe he was poisoned. Franklin D. Roosevelt was elected four times (1932,1936, 1940 and 1944), the only man to serve so long a term. He had contracted polio in 1921 and eventually died of the illness in 1945.

Ronald Reagan, who was elected in 1980 and reelected four years later, suffered an assassination attempt but did not succumb to the assassin's bullets. He was the first to break the long chain of unfortunate events. Will the candidate in the election of 2020 also be as lucky?

The word "assassinated" in the second paragraph is closest in meaning to ____

A. sickened                   

B. honored           

C. decorated                  

D. murdered

Mark the letter A, B, C, or D on your answer sheet to indicate the most suitable response to each of the following exchanges

"Oops! I’m sorry for stepping on your foot" – “______.”

A. Never mind  

B. You don't mind  

C. You're welcome  

D. That's fine 

Read the following passage on commuting, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 51 to 60.

Many folk cures which have been around for centuries may be more therapeutic than previously suspected. A case in point is that of penicillin Alexander Fleming did not just randomly choose cheese molds to study when he discovered this very important bacteria-killing substance. Moldy cheese was frequently given to patients as a remedy for illness at one time Fleming just isolated what it was about the cheese which cured the patients.

In parts of South America, a powder obtained from grinding sugar cane is used for healing infections in wounds and ulcers. This usage may date back to pre-Colombian times. Experiments carried out on several hundred patients indicate that ordinary sugar in high concentrations is lethal to bacteria. Its suction effect eliminates dead cells and it generates a glasslike layer which protects the wound and ensures healing.

Another example of folk medicine which scientists are investigating is that of Arab fishermen who rub their wounds with a venomous catfish to quicken healing. This catfish excretes a gellike slime which scientist found to contain antibiotics coagulant that helps close injured blood vessels, anti-inflammatory agents, and a chemical that directs production of a glue-like material that aids healing.

It is hoped that by documenting these folk remedies and experimenting to see if results are indeed beneficial, an analysis of the substance be made, and synthetic substances be developed for human consumption.

 The first paragraph is mainly concerned with which of the following?

A. factors contributing to the decline in MBA students 

B. Two decades of hard times for business schools 

C. The difference between Harvard, Princeton, and Stanford 

D. A current trend affecting the nation’s business schools