Increasing the price is a practical and efficient choice.

Increasing the price is a practical and efficient choice.
里面为什么用increasing而不是 increase呢,它在这里做什么成分呢?
Increasing the price这个整体做为主语出现,因为简单句中只能有一个动词,即is,所以increase此时不能以动词出现,只能用动名词.