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注浆用砂浆配合比中，水泥：砂宜为1:1～1:2，水灰比宜为0.38～0.45。 ()
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设有如下图所示的两个关系S(sno，sname，Sex)和SC(sno，cno，grade)。其中关系S的主码是sno，关系SC的主码是(sno，cno)。且关系SC的属性"sno"是它的外码。要求 grade的取值只能是0～100之间的整数。关系S
关系数据库必须满足以下3类完整性规则：
Ⅰ．实体完整性规则
Ⅱ．参照完整性规则
Ⅲ．用户定义的完整性规则
上述两个关系违背了哪个(些)完整性规则？
听力原文：M: What do you mean by a friend, Jean？
W: Oh, Robert, to me, friendship is the most important thing in life. It's more important even than love. If you love someone, you can always fall out of love again, and that can lead to a lot of hurt feelings, bitterness, and so on. But a good friend is a friend for life.
M: Someone who likes the same things that you do, who can argue with and not lose your temper, even if you don't always agree about things. I mean someone who you don't have to talk to all the time but can be silent with, perhaps. That's important, too. You can just sit together and not say very much sometimes. Just relax. I don't like people who talk all the time.
W: Are you very good at keeping in touch with your friends if you don't see them regularly？
M: No, not always. I've lived in lots of places, and, to be honest, once I move away, I often do drift out of touch with my friends. And I'm not a very good letter writer, either. Never have been. But I know that if I saw those friends again, if I ever moved back to the same place, or for stone other mason we got back into close contact again, I'm sure the friendship would be just as strong as it was before.
W: Several of my friends have moved away, got married, things like that. One of my friends has had a baby recently, and I'll admit I don't see her or hear from her as much as I used to...She lives in another neighborhood and when I phone her, she always seems busy. But that's an exception. I write a lot of letters to my friends and get a lot of letters from them. I have a friend I went to school with and ten years ago she emigrated to Canada, but she still writes to me every month, and I write to her just as often.
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A．House painter.B．Salesman.C．Mailman.D．Milkman.
Section B
Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You should decide on the best choice.
The Chinese of 3500 years ago believed that the earth was a chariot, and the sky, a curved canopy stretched above it. The canopy was nine layers thick, and it sloped slightly to the northwest, as a cataclysm had broken one of its supporting columns. This gentle slope explained the movement of the stars from east to west.
According to these ancient Chinese beliefs, the sun spent the night on earth and ascended to the sky each morning from the luminous valley of the east by climbing the branches of an immensely tall sacred tree. To the Chinese people, the sun was the incarnation of goodness, beauty, and truth. In popular imagination, the sun was represented as a cock that little by little assumed human form. His battles with the dragons, which was personified evil in their beliefs, accounted for the momentary disappearances of the sun that men now call eclipses. Many of the Chinese people worshiped the sun, but in the vast and complicated organization of the Chinese gods, the sun was of only secondary importance.
Along with these unsophisticated beliefs about the sun, the Chinese evolved a science of astronomy based upon observation, though essentially religious-which enabled them to predict eclipses of the sun and the movements of the stars. Such predictions were based on calculations made by using a gnomon—an object whose shadow could be used as a measure, as with a sundial(日晷仪) or simpler shadow pointers. Moreover, with the naked eye, the Chinese observed sunspots, a phenomenon not then known to their contemporaries.
The ancient Chinese believed that the earth______.
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