【正确答案】 D

【答案解析】[听力原文]77-79 This urgent item just in. The electricity company warns citizens living in the tri-state region that due to unusually high temperatures, the demand for electricity may exceed the supply. Air conditioners and fans are in constant use during this hot summer weather, putting an enormous strain on electricity supply. This increase in demand for electricity may result in power failures in scattered areas throughout the region. In order to help avoid blackouts, citizens are asked to keep their air conditioners set at temperatures no lower than 80 degrees Fahrenheit and to run them only intermittently during the hottest part of the day. In addition, any non essential use of electrical appliances should be avoided during the middle of the day. If a power failure occurring in your neighborhood should cause a potentially life-threatening emergency, call the electricity company's emergency hotline at 555-9745. Emergency workers are standing by in your area ready to respond where needed. This news item is a warning about electrical demand exceeding supply. Choices (A), (B), and (C) are incorrect because the second sentence uses the verb warn, and there is no evident analysis, review, or correction.

【正确答案】 B

【答案解析】Summer is when this would be heard because it is in the present tense and hot summer, air conditioners, and fans are all mentioned. Choices (A), (C), and (D) are incorrect because the tense is in the present.

【正确答案】 A

【答案解析】When excessive use exceeds supply, then a power failure occurs. Choices (B) and (C) repeat the words demand and supply but are the opposite of what causes failure. Choice (D) uses the word fans, but poor quality is not mentioned as a reason for power failure.