B Events such as hurricanes, earthquakes, floods, volcanic eruptions, and tornadoes are all natural disasters. They are mostly related to the weather. Some are predictable ----like a hurricane. Some, like an earthquake, surprise us. It is necessary for us to learn about them, so we can be prepared! Flooding happens during heavy rains, when rivers overflow, when ocean waves come onshore, when snow melts too fast or when dams or banks break. Flooding is the most common of all natural disasters. Hurricanes are severe tropical storms that form in the southern Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and in the Pacific Ocean. Hurricanes gather heat and energy through contact with warm ocean waters. Evaporation(蒸发) from the sea water increases their power. Hurricanes have winds at least 74 miles per hour. When they come onto land, the heavy rain, strong winds and heavy waves can damage buildings, trees and cars. Tornadoes are nature’s most violent storms. Tornadoes must always be taken seriously. Tornadoes can be very dangerous ---- sometimes even deadly. They come from powerful thunderstorms and appear as moving. Tornado winds can reach 300 miles per hour. They cause damage when they land the ground. They can damage an area one mile wide and 50 miles long. While thunder won't hurt you ----lightning will! So it's important to pay attention when you hear thunder. Thunderstorms happen mostly in summer and every thunderstorm has lightning. Lightning can strike people and buildings, which is very dangerous. Thunderstorms affect small areas when compared with hurricanes and winter storms. The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. A volcano is a mountain with a large opening at the top through which melting rock, steam, gases escape from time to time with violent force from inside the earth. When pressure increases, eruptions occur. Gases and rock shoot up through the opening fill the air with small pieces. Erupt  ions can cause lava flows, hot ash flows, mudslides, falling ash and floods, which is likely to knock down entire forests, cause floods and earthquakes. Fresh volcanic ash can cause damage to the lungs of older people, babies and people with respiratory problems.64. From the passage, we know that ______. A. all natural disasters can be predicted B. all natural disasters are connected with the weather. C. human beings can do nothing with natural disasters D. the more we know about natural disasters, the less we will suffer. 65. Which of the following is NOT true according to the passage? A. Flooding is the most common natural disaster. B. Hurricanes and tornadoes can land the ground and cause damage. C. Thunder can strike people and buildings. D. Fresh volcanic ash can cause illnesses. |