简并（degeneracy）
参考答案：
一个氨基酸由一个以上的三联体密码所决定的现象。
---Could you tell me ________?
---Sorry. I don’t know. I didn’t attend the meeting.
A．what did he say at the meeting
B．what had he said at the meeting
C．what he said at the meeting
D．what he would say at the meeting
ERP系统
