- 搜標(biāo)題
- 搜題干
- 搜選項
單項選擇題
列車運(yùn)行監(jiān)控裝置的時鐘，允許走時誤差：＜（）
A.20s
B.30s
C.40s
D.50s
A.20s
B.30s
C.40s
D.50s
