氨基酸注射液通常必需氨基酸和非必需氨基酸的含量比是（）。
A.1：1
B.1：2
C.1：3
D.1：4
E.1：5
参考答案：B
1. Every possible means should be made full use of _______ the lives of the injured people in subway tunnel collapse
A．rescuing
B．to rescue
C．rescue
D．being rescued
A．mgtgθ
B．mgsinθ
C．μmg
D．μmg
mgtgθ
mgsinθ