色氨酸的三个字母符号为()。
A.Gly
B.Ala
C.Leu
D.Try
E.Thy
参考答案:D
As the noises are ________ of big cities, some people prefer to live in the countryside. [ ]
A. characteristic
B. particular
C. familiar
D. special
手动工具的接地线,()应进行检查。
A、每次使用前
B、每年
C、每月
D、每周