发动机工作时，若供给的是稀混合气，废气中便有较多的（）A、空气 B、氮气 C、氧气

1.She tried to _____ out of the window to see the procession more clearly.

A. bend            B. lean          C. bow           D. slope

2．Throughout most of their lives, humans _____ learn and increase their mental capacity.

A. actually        B. readily        C. fairly       D. primarily

------ Where’s the best place to meet?

------ What about ______ outside the cinema?

A．meeting

B．to meet

C．meet

D．met

某工程双代号网络计划如下图所示，其关键线路有（）条。

A．1

B．2

C．3

D．4

以社会保险作为基本纲领的是______。

A．社会保障
B．社会福利
C．社会救助
D．社会优抚

巷道掘进施工如遇井下条件变化时，必须按补充安全技术措施施工。（）