The story shows that knowledge of first aid can make real difference.A. the; the; /B. a

问题补充：

The story shows that knowledge of first aid can make real difference.

A. the; the; /

B. a; /; a

C. /; the; a

D. a; /; /

答案：

A. the; the; /

(答案→)B. a; /; a

C. /; the; a

D. a; /; /

解析：

这题考查冠词的用法：第一空填a，a knowledge of是“知道,了解”，第二空不填，是泛指“急救”，第三空填a，make a real difference.是固定词组“真的有影响”。