HIV
基因编码
A．反转录酶B．蛋白酶C．两者均是D．两者均非
参考答案：C
------Hi, Kate! Glad you could make it to the party.
------______________
------ You were the first person I thought of.
A．Thanks for inviting.
B．It looks as if the party has already started.
C．Let me give you my coat.
D．It’s always a pleasure to make a new friend.
自然富集
基因编码
基因编码