Read the following passage and mark the letter A, B, C ,or D on your answer sheet to indicate the correct answer for each of the questions.
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
A. in the receptors of the ants
B. just above the trail
C. in the source of food
D. under the soil along the trail
Giải bởi qa.haylamdo.com
Đáp án B
Dịch: Theo bài viết, lượng pheromones cao nhất có thể tìm thấy ở
A. Bộ phận thủ cảm của kiến
B. Ngay phía trên đường dấu
C. Nguồn thức ăn
D. Ngay dưới đất dọc theo đường dấu
Thông tin nằm ở đoạn 3: A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. (Một đường dấu pheromone sẽ bốc hơi để tạo ra một lượng tập trung cao nhất của chất này ngay phía trên đường dấu, gọi là vùng không gian khí hơi).
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
He takes four paracetamol everyday, not knowing that will seriously damage his liver.
I can’t stand the car ____________ Therefore, I hate traveling by car.
Read the passage and choose the best option to complete each blank.
Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes ____46___ ecosystems. If there is too little rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals ____47___ feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fires for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds ____48___. Polluting the air, soil, and water can harm ecosystems. Building dams on rivers for electric power and irrigation can harm ecosystems ____49___ the rivers. Bulldozing wetlands and cutting down forests destroy ecosystems. Ecologists are working with companies and governments to find better ways of ___50____ fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people without causing harm to ecosystems.
Điền vào số (49)
It was …… easy for him to learn baseball because he had been a cricket player.'
Read the passage and choose the best option to complete each blank.
Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes ____46___ ecosystems. If there is too little rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals ____47___ feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fires for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds ____48___. Polluting the air, soil, and water can harm ecosystems. Building dams on rivers for electric power and irrigation can harm ecosystems ____49___ the rivers. Bulldozing wetlands and cutting down forests destroy ecosystems. Ecologists are working with companies and governments to find better ways of ___50____ fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people without causing harm to ecosystems.
Điền vào số (46)
Mark the letter A, B, C, or D to identify the word whose stress pattern is different from that of the other words in the same group.
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 .
Martin Luther King, Jf., is well- known for his work in civil rights and for his many famous speeches, among which is his moving “ I have a dream” speech. But fewer people know much about King’s childhood. M.L., as he was called, was born in 1929 in Atlanta, Georgia, at the home of his maternal grandfather. M.L.’s grandfather purchased their home on Auburn Avenue in 1909, twenty years before M.L was born. His grandfather allowed the house to be used as a meeting place for a number of organizations dedicated to the education and social advancement of blacks. M.L. grew up in the atmosphere, with his home being used as a community gathering place, and was no doubt influenced by it.
M.L.’s childhood was not especially eventfully. His father was a minister and his mother was a musician. He was the second of three children, and he attended all black schools in a black neighborhood. The neighborhood was not poor, however. Auburn Avenue was an area of banks, insurance companies, builders, jewelers, tailors, doctors, lawyers, and other businesses and services. Even in the face of Atlanta’s segregation, the district thrived. Dr. King never forgot the community spirit he had known as a child, nor did he forget the racial prejudice that was a huge barrier keeping black Atlantans from mingling with whites.
What is Martin Luthur King well- known for?
Christine ...... have arrived by now, she..... have missed the bus.
Mark the letter A, B, C, or D on you answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
He is very intelligent. He can solve all the problems in no time.
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
Caroline has worn her new yellow dress only once since she buys it.
Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is CLOSET in meaning to the underlined part in each of the following questions.
His new yacht is certainly an ostentatious display of his wealth.
Choose the word whose underlined part is pronounced differently from others
