I am a beginner in English. I read this sentence in an example: "If you work at a job you enjoy, you will probably do your job better than if you work at a job only to earn money.". Why do we use "to earn" and not "earn"?
Learn English – When we should add “to” before verb
infinitivesto-infinitive
Best Answer
Generally, the question of whether to use the infinitive with "to" or the infinitive without "to" depends on the particular word (verb, adjective, noun) which commands the phrase, and you just have to learn that.
For example, modals, such as should, must, take an infinitive without "to", while verbs like ought, have (to) require the "to", even though they mean pretty much the same:
But your example is different: this is the use of the "to"-infinitive to express purpose; "work ... to earn money" means "work ... in order to earn money", or "work ... for the purpose of earning money".
Your example wouldn't be grammatical without the "to", because there would be no grammatical structure for the "earn" to fit into.