驼峰调车场信号设备所使用的电源设备,()采用大站电气集中所用的电源屏。
A.调压屏、交流屏
B.直流屏、转换屏
C.直流屏、交流屏
D.调压屏、转换屏
参考答案:A
It is important for students to get _________. [ ]
A. enough sleepy
B. enough sleep
C. sleep enough
D. sleepy enough
百日咳最易发病的年龄是()
A.1岁以内
B.3岁以内
C.2岁以内
D.5岁以内
E.7岁以内