下面有关E-R模型向关系模型转换的叙述中,正确的是( )。
A. 一个实体类型转换为一个关系模式
B. 一个1:1联系可以转换为一个独立的关系模式,也可以与联系的任意一端实体所对应的关系模式合并
C. 一个1:n联系可以转换为一个独立的关系模式,也可以与联系的任意一端实体所对应的关系模式合并
D. 一个m:n联系转换为一个关系模式
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I was doing my homework_______my brother ran in.
A. while
B. when
C. as
D. because
__ you sleep for a while , you'll feel better.
A. While
B. As
C. After
D. Since
He didn't get up__________l went to wake him up.
A. until
B. after
C. when
D. as
lf you__________tomorrow, I'll tell you the news.
A. will come
B. are going to come
C. is coming
D. come