反密码子是指[ ]
A．DNA上三个相邻的碱基对
B．mRNA上三个相邻的碱基
C．tRNA上的三个碱基RNA
D．rRNA上的三个碱基
答案：C
HS-DPCCH的功率控制采用（）。
The students in our school expected ______ more time for reviews and exercises before the College Entrance Examination next year.
A．there being
B．there has
C．there had
D．there to be
