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【单选题】
R为四元关系R(A,B,C,D),S为三元关系S(B,C,D),R∞S构成的结构集为 ( )元关系A.
3
B.
4
C.
7
D.
12
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【单选题】— It’s said that TV program National Treasure was quite popular. —Yes, I watched ________ at eight last Sunday.
A.
it
B.
them
C.
that
【简答题】Mr Brown likes to be exact (确切的). One day when he took a walk in the street , a man came up and asked him the way to the bookshop . He said to him , "Cross the bridge (过桥) and turn to the right . "The...
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