DNA三联体GCT互补于tRNA的反密码子()
A.GCT
B.CGA
C.CGC
D.GCU
参考答案:D
设学生关系S(sno,sname,sex,dept)的主码为sno,学生选课关系SC(sno,cno,grade)的主码为(sno,cno),则关系模式R(sno,cno,sex,dept,grade)最高属于( )。
A.1NF
B.2NF
C.3NF
D.BCNF
—Is there _____ in today's newspaper?
—Yes, our National Table Tennis Team won all the seven gold medals once more. [ ]
A. something new
B. anything new
C. somebody special
D. anybody special