青藏地区与其他三个地区的大致界线是[ ]
A.大兴安岭—太行山—巫山—雪峰山
B.大兴安岭—阴山—贺兰山
C.昆仑山—祁连山—横断山脉
D.秦岭—淮河
答案:C
They had to operate _______his arm because it was broken in two places.
A.with
B./
C.at
D.on
断指再植的冷缺血时间可长达多久后仍可再植成功()
A.12小时
B.30小时
C.48小时
D.56小时
E.100小时