Soon after becoming a member, Viet Nam signed the Treaty on the Southeast Asian Nuclear

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that is closest in meaning to the following question

As soon as he waved his hand, she turned away.

After the campaign, a special medal was ……. to all people involved.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks

To many people, their friends are the most important in their life. Really good friends always (1)………..joys and sorrows with you and never turn their backs on you. Your best friend may be someone you have known all your life or someone you have grown (2)………..with. There are all sorts of things that can bring about this special (3)……………….. It may be the result of enjoying the same activities and sharing experiences. Most of (4).................. have met someone that we have immediately felt relaxed with as if we had known them for ages. However, it really takes you years to get to know someone well (5)…………to consider your best friend. To the majority of us, this is someone we trust completely and (6)…………….understands us better than anyone else. It's the person you can tell him or her your most intimate secrets.

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

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled- a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.However, human production usually occurs in a localized area, such as a city. In such region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word "detectable " is closest in meaning to

The word "localized " is closest in meaning to

According to the passage, the numerical value of the concentration level of a substance is only useful if ______.