Hỗn hợp X gồm O₂ và O₃. Phân huỷ X thu được một khí duy nhất có thể tích tăng 2% so với thể tích ban đầu. Phần trăm thể tích ozon trong hỗn hợp ban đầu là

A. 2%

B. 3%

C. 5%

D. 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.

Long ago prehistoric man began to domesticate a number of wild plants and animals for his own use. This not only provided a more abundant food source but also allowed more people to live on a smaller plot of ground. We tend to forget that all of our present-day pets, livestock, and food plants were taken from the wild and developed into the forms we know today.

As centuries passed and human cultures evolved and blossomed, humans began to organise their knowledge of nature into the broad field of natural history. One aspect of early natural history concerned the use of plants for drugs and medicine. The early herbalists sometimes overworked their imaginations in this respect. For example, it was widely believed that a plant or part of a plant that resembles an internal organ would cure ailments of that organ. Thus, an extract made from a heartshaped leaf might be prescribed for a person suffering from heart problems.

Nevertheless, the overall contributions of these early observers provided the rudiments of our present knowledge of drugs and their uses.

The word "This" in the first paragraph refers to________.

A. providing food for man

B. man's domestication of plants and animals

C. man's ability to live on a small plot of land

D. the earliest condition of prehistoric man

* 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 43 to 50.

  “They told me I could never walk again. But when I listened to music, I forgot all about the pain. I found the strength I didn’t know I had.”Ninety-two-year-old Tina Goodman, who regained her ability to walk, thanks to music.

  This is just one of the many stories in Fettaro’s book “The Healing Power of Music” . Fettaro tries to show just how important music is in our lives and how it can help us to be healthy and happy.

  According to Fettaro, music can make sick people again. In fact, his book comes with a CD of recordings, each one specially designed to help with a number of health problems.

  Fettaro, e well-known music therapist, promises that by reading his book, you will be able to develop the healing power of music in your life. He says this will help you fight headaches and back pain, as well as reduce stress, high blood pressure, and many other common illnesses.

  Certainly, I accept that listening to certain types of music can help with particular problems, such as stress. I am also comfortable with Fettaro’s claim that by reading his book, you’ll be able to create a peaceful enviroment to help you relax in your home. I found the relaxation and breathing techniques very useful. Similarly his claim that music help you sleep better seems reasonable. Yet when he goes on to promise his music therapies will help cure depression and even cancer, he begins to sound a little bit unbelievable.

  Nevertheless, for those of you who are interested in the power of music to heal, this is a great book to buy. It’s a thorough introduction to the history and practice of music therapy. Fettaro writes in a simple, easy to understand way and shows clearly how music can affect us positively. His basic message-that music can improve our lives-is well-presented and clear. It may even be true that certain techniques covered here can help some people recover from unpleasant health problems. However, his promises of “amazing results” seem impossible to justify.

Which statement is not true?

A. Music can help you sleep better 

B. Music has positive effects 

C. It is necessary to create a peaceful enviroment when you read Fettaro’s book 

D. The recordings accompanied with the book are to help with some health problems.

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50

Traditionally in America, helping the poor was a matter for private charities or local governments. Arriving immigrants depended mainly on predecessors from their homeland to help them start a new life. In the late 19^th and early 20^th centuries, several European nations instituted public-welfare programs. But such a movement was slow to take hold in the United States because the rapid pace of industrialization and the ready availability of farmland seemed to confirm the belief that anyone who was willing to work could find a job.

Most of the programs started during the Depression era were temporary relief measures, but one of the programs - Social Security - has become an American institution. Paid for by deductions from the paychecks of working people, Social Security ensures that retired persons receive a modest monthly income and also provides unemployment insurance, disability insurance, and other assistance to those who need it. Social Security payments to retired persons can start at age 62, but many wait until age 65, when the payments are slightly higher. Recently, there has been concern that the Social Security fund may not have enough money to fulfill its obligations in the 21st century, when the population of elderly Americans is expected to increase dramatically. Policy makers have proposed various ways to make up the anticipated deficit, but a long-term solution is still being debated.

In the years since Roosevelt, other American presidents have established assistance programs. These include Medicaid and Medicare; food stamps, certificates that people can use to purchase food; and public housing which is built at federal expense and made available to persons on low incomes.

Needy Americans can also turn to sources other than the government for help. A broad spectrum of private charities and voluntary organizations is available. Volunteerism is on the rise in the United States, especially among retired persons. It is estimated that almost 50 percent of Americans over age 18 do volunteer work, and nearly 75 percent of U.S. households contribute money to charity.

New immigrants to the U.S. could seek help from ______. 

A. the people who came earlier

B. the US government agencies 

C. only charity organizations

D. volunteer organizations