Everyone should learn something about first aid for every second willin an emergency.A

问题补充：

Everyone should learn something about first aid, for every second willin an emergency.

Aplay

B. count

Chappen

Dshow

答案：

A. play

(答案→)B. count

C. happen

D. show

解析：句意，每个人都应该学习一些有关急救的知识，因为在紧急情况下每一秒都很有价值。Play玩 count有价值 happen 发生 show演示，根据语意选B项。