be prone to 的to 是作介词还是不定式?

题目

be prone to 的to 是作介词还是不定式?
例句中有be prone to illness 也有be prone to eat junk food
就是说既有be prone to do sth.也有be prone to n.那to到底是作什么?如果说be prone to doing 是正确的吗?

答案

‘To’ is not an infinitive marker but a preposition in your sentences.What follows a preposition should normally be a noun or noun phrase.‘Prone’ is one of those few adjectives like ‘inclined’ or ‘consent’ used with ‘to’ and followed by a bare verb like an infinitive
I would say ;This plant is prone to attack (as a noun not a verb) by insects
翻译就是
to是个介词,后面跟名词或名词词组.Prone是极少数能和to连用,后面跟不带to的动词不定式（动词原形）.
be prone to eat(eat是不带to的动词不定式,做名词） junk food
另外意思也有区别
infinitive:This plant is prone to attack by insects.
meaning,insects might attack the plant.（昆虫也许会侵害树木）（以前没侵害过）
gerund:This plant is prone to being attacked by insects.
meaning:insects have attacked the plant before.（昆虫也许会侵害树木）（昆虫以前就侵害过树木）
BE + past participle:This plant is prone to be attacked by insects.
meaning,the plant will definitely be attacked by insects.（（昆虫一定会侵害树木）（以前侵害过）
另外上面说的不一定正确,但有95%的把握