使膝关节屈曲的肌肉有（）
A.半腱肌
B.半膜肌
C.小腿三头肌
D.缝匠肌
E.骨直肌
参考答案：A, B, C, D
— I put on my scarf and hat. Why?
— ________________________[ ]
A. Because it's hot outside.
B. Because it's cold outside.
C. Because I am hot.
D. Because I am hungry.
ESD系统（）关断时UPS不间断电源会延时30分钟关断
A、二级
B、一级
C、四级
D、三级
