单选题. Half of the world's coral reefs (珊瑚礁) have died in the last 30 years. Now scientists are racing to ensure that the rest survive. Even if global warming were to stop right now, scientists predict that more than 90% of corals will die by 2050. If no major steps are taken to address the problem, the reefs may be headed for total extinction. The planet's health depends on the survival of coral reefs. They are often described as "the rainforests of the sea", because they provide shelter for a wide variety of sea life. In addition, the reefs serve as barriers that protect coastlines from the full force of powerful storms. Corals are used in medical research for cures to diseases. They are key to local economies as well, since the reefs attract tourists, the fishing industry, and other businesses, bringing in billions of dollars. Corals are particularly sensitive to changes in temperature. A rise of just 1 to 2 degrees can force the corals to drive out the algae (水藻). Then the corals turn white in a process called "bleaching". Corals can recover from short-term bleaching, but long-term bleaching can cause permanent damage. In 1998, when sea surface temperatures were the highest in recorded history, coral reefs around the world suffered the most severe bleaching. It is estimated that even under the best of conditions, many of these coral reefs will need decades to recover. Although reefs face other threats from pollution, industrial activities, and overfishing, it is global climate change that most concerns scientists. Scientists remain hopeful that it's not too late to save the reefs, and some are moving ahead on experiments to accomplish that goal.1. Which of the following is the best title for the passage? ______
单选题 Toronto's third City Hall
单选题20. It's almost five years ______ we saw each other last time.
单选题《复合题被拆开情况》 At some time in your life you may have a strong desire to do something strange or terrible. However, chances are that you don’t act on your impulse冲动, But let it pass instead. You know that
单选题《复合题被拆开情况》 Death Valley is one of the most famous deserts in the United States, covering a wide area with its alkali sand. Almost 20 percent of this area is well below sea level, and Badwater, a salt
单选题《复合题被拆开情况》 Scientists in India have invented a new way to produce electricity. Their invention does not get its power from oil, coal or other fuels. It produces electricity with the power of animals.
单选题Alex: Are you planning on transferring? Bruce: Ye
单选题《复合题被拆开情况》Helen:【D8】________Do you study Chinese at the university here?Rose: Yes, I do. But my characters are very bad.Helen:【D9】________Rose: Are you Chinese?Helen: Yes, I am. I came here to study p
单选题The population of the world is growing at a dangerous________.
单选题《复合题被拆开情况》 Half of the world’s coral reefs珊瑚礁 have died in the last 30 years. Now scientists are racing to ensure that the rest survive. Even if global warming were to stop right now, scientists predi
单选题《复合题被拆开情况》 When we’ re learning a foreign language, making sense of what we hear is the first step toward fluency. It sounds obvious, but until recently, we didn’t know much about how listening works.
单选题It’s hard to remember a name when one doesn’t have a face to go with________.
单选题13. Which one of his books do you think ______ best among the best-sellers?
单选题 I'm awfully tired and can't go any farther, Ted
单选题Ted,________yourself and don’t get your coat dirty again, or you will get into trouble!
单选题《复合题被拆开情况》 In 1991, when announced to be HIV positive, "Magic" Johnson became the face of a disease that the public still had a lot to learn about. The basketball star established the Magic Johnson Fo
单选题《复合题被拆开情况》 Death Valley is one of the most famous deserts in the United States, covering a wide area with its alkali sand. Almost 20 percent of this area is well below sea level, and Badwater, a salt
单选题《复合题被拆开情况》 At some time in your life you may have a strong desire to do something strange or terrible. However, chances are that you don’t act on your impulse冲动, But let it pass instead. You know that
单选题 I'm ______ about how you discovered my website
单选题《复合题被拆开情况》Mark: There is a sailor there. I’m going to ask that sailor if he knows where I can find a boat to Mosquito City.【D1】________Sailor: Yeah. What can I do for you, buddy? Mark:【D2】________Sail