The giving-way vessel has a same meaning of（）.

A.stand-on vessel

B.privileged vessel

C.burdened vessel

D.hampered vessel

脑血栓形成的常见病因是

A．各种脑动脉炎
B．动脉粥样硬化
C．红细胞增多症
D．低血压
E．高血压