15000 bài tập tách từ đề thi thử môn Tiếng Anh có đáp án (Phần 81)

Mark the letter a, B, C, or D on your answer sheet to indicate the sentence that is closest meaning to each of the following questions or indicate the correct answer to each of them

Tsunami is a Japanese word which means harbor wave and is used as the scientific term for seismic sea wave generated by an undersea earthquake or possibly an undersea landslide or volcanic eruption. When the ocean floor is tilted or offset during an earthquake, a set of waves is created similar to the concentric waves generated by an object dropped into the wave. Most tsunamis originate along the Ring of Fire, a zone of volcanoes and seismic activity, 32.500 km long that encircles the Pacific Ocean. Since 1819, about 40 tsunami have struck the Hawaiian Islands.

A tsunami can have wave lengths, or widths, of 100 to 200 km, and may travel hundreds of kilometres across the deep ocean, reaching speeds of about 725 to 800 kilometres an hour. Upon entering shallow coastal waters, the wave, which may have been only about half a metre high out at sea, suddenly grows rapidly. When the wave reaches the shore, it may be 15 metres high or more. Tsunamis have tremendous energy because of the great volume of water affected. They are capable of obliterating coastal settlements.

Tsunami should not be confused with storm surges, which are domes of water that rise underneath hurricanes or cyclones and cause extensive coastal flooding when the storms reach land. Storm surges are particularly devastating if they occur at high tide. A cyclone and accompanying storm surge killed an estimated 500,000 people in Bangladesh in 1970. The tsunami which truck south and southeast Asia in late 2004 killed over 200 thousand people.

Mark the letter a, B, C, or D on your answer sheet to indicate the sentence that is closest meaning to each of the following questions or indicate the correct answer to each of them

It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species’ death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be able to adapt. Food resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.

The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species become extinct at the same time- a mass extinction. One of the best- known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago, when appropriately 95 percent of all species died. Mass extinction can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the ocean. Such a change would probably lead to a mass extinction.

One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability to adapt. If so, some of evolutionary history may reflect a sequence of essentially random events.

 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. 

          Successful students often do the followings while studying. First they have an overview before reading. Next, they look for important information and pay greater attention to it (which often needs jumping forward or backward to process information). They also relate important points to one another. Also, they activate and use their prior knowledge. When they realize that their understanding is not good, they do not wait to change strategies. Last, they can monitor understanding and take action to correct or “ fix-up” mistakes in comprehension.

          Conversely, students with low academic achievement often demonstrate ineffective study skills. They tend to assume a passive role in learning and rely on others(e.g, teachers, parents) to monitor their studying. For example, low-achieving students often do not monitor their understanding of content, they may not be aware of the purpose of studying, and their show little evidence of looking back, or employing “fix-up” strategies to fix understanding problems. Students who struggle with learning new information seem to be unaware that they must extent beyond simply reading the content to understand and remember it. Children with learning disabilities do not plan and judge the quality off their studying. Their studying may be disorganized. Students with learning problems face challenges with personal organization as well. They often have difficulty keeping track of materials and assignments, following directions, and completing work on time. Unlike good student who employ a variety of study skills in a flexible yet purposeful manner, low-achieving students use a restricted range of skills. They can not explain why good study strategies are important for learning, and they tend to use the same, often ineffective, study approach for all learning tasks, ignoring task content, structure of difficulty.