成人短时间内失血达多少时,才引起休克()。
A.400~500ml
B.400~800ml
C.300~800ml
D.800~1000ml
E.1000~1500ml
参考答案:D
--- Why didn’t she ask for help at that time?
--- You know, at such a midnight, there was no one ________.
A.she could turn to
B.for whom to turn
C.who to turn to
D.for her to turn
飞行员通过什么操纵机构来操纵旋翼桨叶绕其轴向转动以改变桨叶迎角()?
A.总桨距杆
B.脚蹬
C.驾驶杆