一个SAT语法的疑惑

题目

一个SAT语法的疑惑
道底什么时候动词可以加ing,咱们在国内学的除了有些固定搭配,就是什么正在进行时都必须动词加ing,但我最近做SAT语法题有好多动词没有用am is are 但却是ing的形式,我选他们错吧但大多数他们都没错比如：
The reason for dramatically (raising) fines for litering is that many pet owners would simply decide to pay them rather thatn pick up their pet's waste.比如这里的raise为什么就加了ing就没错呢.

答案

你这句是介词for后跟的动名词形式.介词后面如果跟个动词,就要就ING也就是动名词形式.dramatically是个副词,用来修饰后面这个动名词.另有一类情况就是从句改成的ING形式.如：The boy (who is standing under the tree...