遗传学上将某种分子上决定一个氨基酸的三个相邻碱基称为“密码子”，这种分子是 [ ]
A．肽链
B．DNA
C．信使RNA
D．转运RNA
答案：C
根据句意及首字母提示补全句子。
1.They are having a good t________ in the party.
2.The opposite of right is w________.
3.The brothers are f________ with each other because of the money that are left by their parents.
4.The police jumped into the river in order to s________ the little boy.
5.He is a very p________ teacher.All the students like him.
—_____
—I have a tooth ache. [ ]
A. Can I help you?
B. What's wrong?
C. What do you have?
