口腔颌面颈部的静脉

A．分为浅静脉和深静脉两类

B．浅静脉接受浅层组织的血液，汇人深静脉

C．静脉血主要通过颈内静脉和颈外静脉向心脏回流

D．静脉的行径、分布大多与动脉一致

E．面部静脉较少，变异相对较少

This is not my watch. Do you know _____ it is?[ ]

A. what

B. which

C. who

D. whose