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【单选题】在一个E-R图中,如果共有20个不同实体类型,在这些实体类型之间存在着9个不同的二元联系(二元联系是指两个实体之间的联系)其中3个是1:n联系,6个是m:n联系,还存在1个m:n的三元联系,那么根据E-R模型转换成关系模型的规则,这个E-R结构转换成的关系模型个数为
A.
20
B.
27
C.
30
D.
36
【简答题】在E-R模型中,实体之间的联系类型有( )、( )和( )。
【简答题】在E-R模型中,实体之间的联系类型有____、____、____。
【单选题】The loud noise outside ______ our teacher’s voice so that we didn’t ______ what he was saying. [     ]
A.
put out; hear
B.
drowned; make out
C.
cut out; recognize
D.
threw away; know
【简答题】在E-R模型中,实体之间的联系类型有________、________和________。
【判断题】普通斜交胎的帘布层数越多,强度越大,但弹性越差。
A.
正确
B.
错误
【单选题】Without our teacher's help, we ______ so much.
A.
didn't achieve
B.
will not achieve
C.
don't achieve
D.
would not have achieved
【单选题】Our teacher asked me ________. [     ]
A.
what was Ann doing these days
B.
why Peter didn’t come to school the day before
C.
when will the dolphin show begin
D.
how long I usually spent on my homework
【单选题】i didn’t like our new english teacher, and ____.
A.
neither did my classmates
B.
neither my classmates did
C.
my classmates don’t too
D.
my classmates did not also
【单选题】I didn’t like our new English teacher, and ____.
A.
neither did my classmates
B.
neither my classmates did
C.
my classmates don't too
D.
my classmates did not also
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