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【简答题】
关系数据库的 规则规定:基本关系的主属性不能取空,关系数据库的 规则规定:一个基本关系的外码(对应于另一个基本关系的主码)取值取空值或者必须等于它所对应基本关系中的主码值。
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举一反三
【单选题】一I'm sorry, I was late. —________. [     ]
A.
Not at all
B.
It doesn't matter
C.
Of course not
D.
Don't mention it
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【多选题】微波半导体器件缺点是()
A.
频率低
B.
制造工艺复杂
C.
成本高
D.
功率不易提高
查看完整题目与答案
【单选题】一I'm sorry, sir, but smoking is forbidden in the library. --- Oh, _______, I forgot.
A.
never mind
B.
it doesn't matter
C.
that's all right
D.
I'm sorry
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【简答题】根据中文意思完成句子。 1. 对不起，我迟到了。 I'm sorry I ________ class. 2. 迈克，放学后和我一块去购物怎么样？ ________ going shopping with me after school, Mike? 3. 我每天都花半小时步行上学。 ________ 30 minutes to walk to school every day. 4. 学生们都在...
查看完整题目与答案
【简答题】补全对话，每空一词。 A: Hi, Mike! Could you please play ping-pong with me? B: I'm sorry, but I 1 . A: Why? B: I have to stay at home to look 2 my granny. A: 3 the matter with her? B: She said she had a cold. A:...
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【单选题】-I'm sorry I made a mistake! 一 _▲ Nobody is perfect.
A.
Take your time.
B.
You're right.
C.
Whatever you say.
D.
Take it easy.
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【单选题】一I'm sorry, but there is no smoking on this Alight.-Oh, I____ that. Sorry, I won't again.
A.
don't know
B.
didn't know
C.
won't know
D.
haven't known
查看完整题目与答案
【简答题】根据中文意思完成句子。 1. 很抱歉今天不能陪你去购物，明天怎么样？ I'm sorry I can't go shopping with you today. ________________________ tomorrow? 2. 多吃水果和蔬菜对身体有好处。 ________________________ our health to eat more fruit and vegetabl...
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【单选题】一James, I'm sorry I used your computer when you were away this morming.-______.
A.
That's all right
B.
It's a pleasure
C.
You are welcome
D.
Don't mention it
查看完整题目与答案
【简答题】’ 一I'm sorry I _______ my homework at home.一That's all right. Don't forget _______ it to school tomorrow.A. forgot; bringing B. left; to bring C. left; bringing D. forgot; to bring
查看完整题目与答案
相关题目：
【单选题】一I'm sorry, I was late. —________. [     ]
A.
Not at all
B.
It doesn't matter
C.
Of course not
D.
Don't mention it
查看完整题目与答案
【多选题】微波半导体器件缺点是()
A.
频率低
B.
制造工艺复杂
C.
成本高
D.
功率不易提高
查看完整题目与答案
【单选题】一I'm sorry, sir, but smoking is forbidden in the library. --- Oh, _______, I forgot.
A.
never mind
B.
it doesn't matter
C.
that's all right
D.
I'm sorry
查看完整题目与答案
【简答题】根据中文意思完成句子。 1. 对不起，我迟到了。 I'm sorry I ________ class. 2. 迈克，放学后和我一块去购物怎么样？ ________ going shopping with me after school, Mike? 3. 我每天都花半小时步行上学。 ________ 30 minutes to walk to school every day. 4. 学生们都在...
查看完整题目与答案
【简答题】补全对话，每空一词。 A: Hi, Mike! Could you please play ping-pong with me? B: I'm sorry, but I 1 . A: Why? B: I have to stay at home to look 2 my granny. A: 3 the matter with her? B: She said she had a cold. A:...
查看完整题目与答案
【单选题】-I'm sorry I made a mistake! 一 _▲ Nobody is perfect.
A.
Take your time.
B.
You're right.
C.
Whatever you say.
D.
Take it easy.
查看完整题目与答案
【单选题】一I'm sorry, but there is no smoking on this Alight.-Oh, I____ that. Sorry, I won't again.
A.
don't know
B.
didn't know
C.
won't know
D.
haven't known
查看完整题目与答案
【简答题】根据中文意思完成句子。 1. 很抱歉今天不能陪你去购物，明天怎么样？ I'm sorry I can't go shopping with you today. ________________________ tomorrow? 2. 多吃水果和蔬菜对身体有好处。 ________________________ our health to eat more fruit and vegetabl...
查看完整题目与答案
【单选题】一James, I'm sorry I used your computer when you were away this morming.-______.
A.
That's all right
B.
It's a pleasure
C.
You are welcome
D.
Don't mention it
查看完整题目与答案
【简答题】’ 一I'm sorry I _______ my homework at home.一That's all right. Don't forget _______ it to school tomorrow.A. forgot; bringing B. left; to bring C. left; bringing D. forgot; to bring
查看完整题目与答案