问题 多选题

朝鲜的“核危机”引起了全世界的瞩目,其焦点问题就是朝鲜核电站采用的是轻水堆还是重水 堆.因为重水堆核电站在发电的同时还可以产出供研制核武器的钚239(),这种可由铀239()经过衰变而产生,则下列判断中正确的是(  )

A.的核内具有相同的中子数

B.的核内具有相同的核子数

C.经过1次α衰变产生

D.经过2次β衰变产生

答案

BD

阅读理解

If you’re planning on traveling, there are a few simple rules about how to make life easier both before and after your journey.

First of all, always check and double-check departure (行程) time. It is amazing how few people really do this carefully. Once I arrived at the airport a few minutes after ten. My secretary had got the ticket for me and I thought she had said that the plane left at 10:50. When I arrived at the airport, the clerk at the departure desk told me that my flight was closed. Therefore, I had to wait three hours for the next one and missed an important meeting.

The second rule is to remember that even in this age of credit cards, it is still important to have at least a little of the local currency (货币) with you when you arrive in a country. This can be necessary if you are flying to a place few tourists normally visit. A few years ago I was sent to Tulsa, Oklahoma. I flew there from London via (经由) Dallas, with very little time to change planes in between. I arrived there at midnight and the bank at the airport was closed. The only way to get to my hotel was by taxi and because I had no dollars, I offered to pay in pounds instead.

“Listen! I only take real money!” the driver said angrily. Luckily I was able to borrow a few dollars from a clerk at the hotel, but it was very embarrassing (令人难堪的).

The third and last rule is to find out as much as you can about the weather at your destination before you leave. I feel sorry for some of my workmates who travel in heavy suits and raincoats in May, when it is still fairly cool in London or Manchester, to places like Athens, Rome or Madrid, where it is already beginning to get quite warm during the day.

40. According to the passage, it’s obvious that ______.

A. the author learns some rules of traveling from his own experience

B. the author doesn’t plan his trips or journeys carefully

C. Englishmen like to wear heavy suits wherever they travel

D. the American taxi driver never travels to England

41. What should you make sure first before setting off?

A. When you will leave.      B. Where you will go.

C. How you will travel.        D. Whom you will go with.

42. What does the underlined word “there” in Paragraph 3 refer to?

A. London.            B. Manchester.            C. Tulsa.        D. Dallas.

43. Which of the following is TRUE according to the passage?

A. The author tells people to choose warm places as their travel destinations.

B. You should remember to take credit cards when traveling.

C. You should know more about the weather of the place you’ll visit.

D. You should take enough change when you travel to another country.

单项选择题