be accustomed to doing的否定为什么是be accustomed to not doing.请详细回答

be accustomed to中的to个介词，后面如接动词，动词要加ing改成动名词。动名词和动词不定式一样，其否定形式也是直接在它前面加not。 如：I get up early in order not to be late for school.I decided not to do the homework.I feel like not being disturbed.I prefer not doing the experiment.