tRNA的CCA序列位于
A．DHU环
B．反密码环
C．T[*]环
D．氨基酸臂
E．额外环
参考答案：D
The weather was warm, the food was inviting and the view was pretty — ____ we had a pleasant holiday.
A．exactly
B．meanwhile
C．finally
D．altogether
节气门阀有什么作用？
