basic first-aid techniques will help you respond quickly to emergencies.
A. Known
B. Having known
C. Knowing
D. Being known
网友回答
A. Known
B. Having known
(答案→)C. Knowing
D. Being known
解析：考查动名词做主语。分析句子成分可知，谓语是will help，所以前面的是主语，用动名词做主语。句意：了解基本的急救知识可以让你尽快的回应紧急状况。所以选C。
【考点定位】考查动名词做主语。