下列血管中有防止血液倒流的瓣膜的是( )
A:肱动脉
B:颈动脉
C:上腔静脉
D:毛细血管
例:
—Do you want some rice?
—Yes, please.
This pair of glasses ______ be Tony 's. He's the only one who wears glasses.
当你用手将食物放入嘴里时,上臂肌肉所处的状态(如图)是( )