[单项选择]下述选项属于数据库设计内容的是
Ⅰ．设计数据库管理系统 Ⅱ．设计数据库概念结构
Ⅲ．设计数据库逻辑结构 Ⅳ．设计数据库物理结构
A. Ⅰ和Ⅱ
B. Ⅱ、Ⅲ和Ⅳ
C. Ⅰ和Ⅲ
D. 都是

Time spent in a bookshop can be most enjoyable, whether you are a book lover or merely there to buy a book as a present. Whatever the person, you can soon become totally aware of your surroundings. You soon become engrossed (吸引) in some books, and usually it is only much later that you realize you have spent far too much time there and must dash off to keep some forgotten appointment--without buying a book, of course.
This opportunity to escape the realities of everyday life is, I think, the main attraction of a bookshop. A music shop is very like a bookshop.’ You can wander round such places to your heart’s content. If it is a good shop, no assistant will approach you with the inevitable greeting: "Can I help you, sir" You needn’t buy anything you don’t want. in a bookshop, an assistant should remain in the background until you have finished browsing. Then, and only then, are his services necessary.
You have to be careful not to
A. Because you want to escape the reality of hard work.
B. Because you are interested in some books and forget time.
C. Because you don’t want to buy a dull book as a present.
D. You are afraid of wasting your money.

I arrived in the United States on February 6,2005 ,but I remember my flint day there very clearly. My plane (36) at Kennedy Airport at three o’clock in the afternoon. The weather was very cold and it was snowing, but I was (37) excited to mind. From the airport, my friend and I (38) a taxi to my hotel. On the way, I saw the skyline of Manhattan for the first time and I stared (39) astonishment at the famous skyscrapers and their (40) beauty. My friend helped me unpack at the hotel and then (41) me soon because he (42) go back to work. He (43) to return the next day.
(44) my friend had left, I went to a restaurant near the hotel to eat something. Because I (45) speak a word of English, I couldn’t (46) the waiter what I wanted. I was very upset and (47) to make some gestures, (48) the waiter didn’t understand me. Finally, I (49) the same thing the man (50)
A. Shortly after
B. Long before 
C. As soon as
D. So long as