Li Lei often goes to school 7:30 in the morning.[ ]
A. at
B. for
C. on
D. of
答案:A
主动脉弓的分支有()
A.右颈总动脉
B.左颈总动脉
C.冠状动脉
D.右锁骨下动脉
E.肺动脉干
多少个trx可以提供容量为10erl,1%的阻塞率?