Question

请问这句子的to 是什么词

Answer 1

更新1:

吾该晒 但我都有些不明 Substitute products constrain the ability of firms in the industry raise their prices substantially. – You can see this is incorrect grammar. 为什么是不能直接用raise 而要加不定词?这个动词应该是在子句
所以是否可用直接动 词
不算遗反两个动词的问题? 另外
是否不定词不是一定为了避免两个动词而用?

substitute products constrain the ability of firms in the dustry to raise their prices substantially 可改写为 Substitute products constrain firms in the industry the (their) ability to raise their prices substantially. to raise their price substantially = an adjective clause 修饰名词 the ability 所以不能只用动词 raise
必须加 to 成为 an adjective clause 与可否用两个动词无关
请问以上to 是否介系词 ? - Yes 如果是介系词
为什么后面不是动名词? – because the preposition “to” is used as part of to-infinitive clause 如果是不定词
为什么要用不定词?因为这是子句
应该可直接用动词 – This is a to-infinitive clause so we cannot just use the verb. Let’s see how the sentence will bee if we just use verb : Substitute products constrain the ability of firms in the industry raise their prices substantially. – You can see this is incorrect grammar. To make it grammatically correct we have to change the verb “raise” to a gerund
with a suitable preposition in front of it : Substitute……ability….. in raising their prices…..
参考: Myself