对于房性期前收缩的治疗，主要采用（） A.奎尼丁 B.普鲁卡因胺 C.胺碘酮

The first two stages in the development of civilized man were probably the invention of weapons and the discovery of fire, although nobody knows exactly when he acquired the use of the ______.

A．latter

B．latest

C．later

D．last

声波遇到异质界面时，在原介质中改变传播方向的现象叫做（）现象

在招标投标中，投标人少于多少个的，招标人应当依照本法重新招标( )

A．2个

B．3个

C．5个

D．10个

我们应该在农历的（）月喝腊八粥。

功能固着