为什么abandon后面只能跟动词的ing形式

因为这是英语中的固定搭配。
abandon doing sth意思是放弃做某事。
例句：
1、Their decision to abandon taking the trip was made because of financial constraints.
他们决定放弃这次出游是因为财力有限。
2、The market might abandon having the stock, and knock down its price.

市场可能会抛售该股票，从而令其股价下跌。

abandon的用法：
他决定放弃这个计划。
　　误：He decided to abandon up the plan.
　　正：He decided to abandon the plan.
　　析：动词 abandon(放弃，抛弃，遗弃)通常不与副词 up 连用。比较：give up the plan(放弃计划)。
　　◎他早年弃文学医。
　　误：In his early days he abandoned medicine to literature.
　　正：In his early days he abandoned medicine for literature.
　　析：abandon sth for sth 指的是主动地为某物而放弃另一物，abandon sth (sb) to sth 则通常指被动地放弃某物而将其被 另一物取得。比较：abandon a city to invaders ( 丢下城市 任入侵者占领)；再比较：abandon oneself to despair(自暴 自弃)。

语法就是这么规定的，abandon后面加的是名词，所以就是ing。
If you abandon a place, thing, or person, you leave the place, thing, or person permanently or for a long time, especially when you should not do so.

采纳哦