<閱讀測驗>第49至52題為題組 Most parts of Taiwan have access to sufficient supplies of fresh water for drinking. But fresh water can be in short supply in many **arid** regions of the world such as Saudi Arabia， where there are limited water resources. As the world population continues to grow， shortages of fresh water will occur more often and the need for additional water supplies will become critical. Some may ask， “Since the ocean covers more than 70 percent of the Earth， why not just get drinking water from the ocean?”” To turn seawater into fresh water， we need to remove the salt in seawater， that is， to desalinate seawater. The problem is that the desalination of water requires a lot of energy. Salt dissolves very easily in water， forming strong chemical bonds， and those bonds are difficult to break. The energy and technology to desalinate water are both expensive， and this means that desalinating water can be costly. There are environmental costs of desalination as well. Sea life can get sucked into desalination plants， killing small ocean creatures like baby fish and plankton， upsetting the food chain. Also， there is the problem of what to do with the separated salt， which is left over as a very concentrated brine. Pumping this super-salty water back into the ocean can harm local aquatic life. Reducing these impacts is possible， but it adds to the costs. Despite the economic and environmental hurdles， desalination is becoming increasingly attractive as human beings are using up fresh water from other sources. At present， desalinating seawater is the only viable way to provide water to growing populations in rural areas of the Middle East and North Africa. Therefore， the race is on to find a cheaper， cleaner， and more energy-efficient way of desalinating seawater， and promising new findings are being reported. 49. Which of the following is closest in meaning to “”**arid**”” in the first paragraph? (A) Occupied. (B) Isolated. (C) Dry. (D) Remote.”
