tailieunhanh - IELTS Academic Reading 39

Thực hành giải IELTS Academic Reading 39 giúp các bạn củng cố lại kiến thức và thử sức mình trước kỳ thi. Hi vọng luyện tập với nội dung đề thi sẽ giúp các bạn đạt kết quả cao trong kì thi sắp tới. Chúc các bạn thi tốt! | IELTS Academic Reading 39 You should spend about 20 minutes on Questions 1-3 which are based on Reading Passage 39 below. Tornadoes Tornadoes are one of the most severe types of weather phenomena. While many people fear tornadoes and their destructive power few people understand their real causes and effects nor are they aware of how to protect themselves from their devastating force. Tornadoes violently rotating columns of air occur when a change in wind direction coupled with an increase in wind speed results in a spinning effect in the lower atmosphere. These whirling movements which may not be visible to the naked eye are exacerbated when the rotating air column shifts from a horizontal to a vertical position. As the revolving cloud draws in the warm air that surrounds it at ground level its spinning motion begins to accelerate thereby creating a funnel that extends from the cloud above it to the ground below. In this way tornadoes become pendent from low pressure storm clouds. When a tornado comes into contact with the ground it produces a strong upward draft known as a vortex a spiraling column of wind that can reach speeds in excess of 200 miles per hour. Traveling across the landscape the tornado wreaks a path of concentrated destruction. It is not uncommon for these twisters to lift heavy objects like cars or large animals and throw them several miles. Houses that succumb to the force of the tornado seem to explode as the low air pressure inside the vortex collides with the normal air pressure inside the buildings. Tornadoes can occur at any time of the year but are typically most frequent during the summer months. Equally tornadoes can happen at any time during the day but usually occur between 3 00 in the afternoon and 9 00 in the evening. While these fierce funnels occur in many parts of the world they are most common in the United States. On average there are 1 200 tornadoes per year in this vast nation causing 70 fatalities and 1 500 injuries. .