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.

Have you ever entered a tropical rainforest? It’s a special, dark place completely different from anywhere else. A rainforest is a place where the trees grow very tall. Millions of kinds of animals, insects, and plants live in the rainforest. It is hot and humid in a rainforest. It rains a lot in the rainforest, but sometimes you don't know it's raining. The trees grow so closely together that rain doesn't always reach the ground.
Rainforests make up only a small part of the Earth's surface, about six percent. They are found in tropical parts of the world. The largest rainforest in the world is the Amazon in South America. The Amazon covers 1.2 billion acres, or almost five million square kilometers. The second largest rainforest is in Western Africa. There are also rainforests in Central America, Southeast Asia, Northeastern Australia, and the Pacific Islands
Rainforests provide us with many things. In fact, the Amazon Rainforest is called the "lungs of our planet" because it produces twenty percent of the world's oxygen. One fifth of the world's fresh water is also found in the Amazon Rainforest. Furthermore, one half of the world's species of animals, plants, and insects live in the Earth's rainforests. Eighty percent of the food we eat first grew in the rainforest. For example, pineapples, bananas, tomatoes, corn, potatoes, chocolate, coffee, and sugar all came from rainforests. Twenty-five percent of the drugs we take when we are sick are made of plants that grow only in rainforests. Some of these drugs are even used to fight and cure cancer. With all the good things we get from rainforests, it's surprising to find that we are destroying our rainforests. In fact, 1.5 acres, or 6,000 square meters, of rainforest disappear every second. The forests are being cut down to make fields for cows, to harvest the plants, and to clear land for farms. Along with losing countless valuable species, the destruction of rainforests creates many problems worldwide. Destruction of rainforests results in more pollution, less rain, and less oxygen for the world

What is the passage mainly about?

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions

We cut down many forests. The Earth becomes hot

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He is very intelligent. He can solve all the problems in no time

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Had she read the reference books, she would have been able to finish the test

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“I will pay back the money, Gloria.” Said Ivan

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It started to rain at 2 o’clock and it is still raining

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I don’t mind waiting for other ten minutes, but will you please keep me company? 

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Caroline has worn her new yellow dress only once since she buys it

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The police told us to refrain from touching the furniture in case they would need to look for fingerprints

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 35 to 42 

     Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 

     Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta Texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 

          The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space.  In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail

According to the passage, the highest amount of pheromone vapor is found _____ 

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 35 to 42 

     Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 

     Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta Texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 

          The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space.  In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail

The word “oscillating” in line 17 is closest in meaning to