单选题 Questions 4 to 7 are based on the following conversation. At the end of the conversation, you will be given 20 seconds to answer the questions.
Now, listen to the conversation.



单选题 What is the most possible reason for the English Channel to emerge?
【正确答案】 A
【答案解析】[听力原文]4-7 M: Mary, can you tell why Britain is separated from the continent? W: I guess I cannot. Maybe millions of years ago, at the end of the Ice Age, a great flood washed over a wide, low plain, and created the English Channel. From then on, the island of Britain was isolated from the rest of Europe. M: I know there have been many people who have wanted to swim across the Channel, and some of them have succeeded. W: What's more, quite a lot of people have thought of building a channel since the 18th century, but no one thought this dream would come true. Now however, the Channel, the longest underwater passage in the world, has been built. M: When did such a miracle occur? W: A British team started to drill southeast from Dover and a French team started to drill northwest from Sangatte in 1987. The two teams met under the Channel in December, 1990, and they celebrated the completion of the 23-mile shaft. The tunnel was not open to the public until 1993 and now it is able to carry up more than 30 million passengers a year. M: How long will it lake to cross the Channel on tile trains? W: Only 26 minutes. In the old days, people had to spend hours on the ferry in rough seas. M: It serves to strengthen tile tie between Britain and the continent, further promote their mutual understanding. W: You are right.
单选题 What is NOT true about the construction of the Channel?
【正确答案】 C
【答案解析】
单选题 How long is the shaft?
【正确答案】 B
【答案解析】
单选题 When was the tunnel opened to the public?
【正确答案】 C
【答案解析】