The Portuguese Gerund [check];
The Present Indicative [check];
The Subjunctive Mood [almost];
Portuguese Prepositions [check!]
Portuguese prepositions? No big deal. Then, you run into an everyday sentence like,
Sem problema, right? I am going to stop of to smoke. Seems wrong. If you know your gerund (the ing ending) you're probably thinking it should be,
Eu vou parar fumando. Now.... if you said this to a Brazilian they would just stand there looking at you with a pleasant expression. Maybe offer you a cold drink, but they won't get what you are saying. That's because there are several very common preposition-verb combinations that are key. I mean, they change the meaning of a sentence radically.
Let's look at three examples that you will hear all_the_time.
Eu vou parar de falar. >> I'm going to stop talking.
Eu quero parar de trabalhar. >> I want to stop working!
Não consigo parar de fazer coisas assim. >> I can't seem to stop doing things like this.
Quando posso começar a namorar? >> When can I start going out?
Para começar a meditar... >> To start meditating...
Quando ela vai começar a trabalhar? >> When is she going to start working?
Eu acabei de terminar com ela. >> I just ended the relationship with her.
Quando você vai acabar de fazer bagunça? >> When are you gong to stop making a mess?
Ele acabou de comer. >> he just finished eating.
Vou escutar sem falar. >> I'm going to listen without talking.
Posso entrar sem pagar? >> Can I enter without paying?
Eu fazia sem pensar. >> I used to do it without thinking
*More on using sem this way Saying without in Portuguese.
Notice how when using these Portuguese prepositions with various verbs the meaning is usually that of ing: talking, working, meditating, etc. You will find yourself trying to sentences similar to these using the gerund, and it will trip you up! The best thing you can do is seek out more examples like these and read them to yourself. Notice how they have a nice flow, a nice sound to them. Now try constructing them using the gerund. They sound ugly and crude, by contrast, Use this as your internal guide. If it sounds bad, look for another way to say it.
Portuguese prepositions & verbs : the ULTIMATE GUIDE
These examples are all part of a GRANDER SCHEME of things -- part of a real grammar RULE: verbs following prepositions need to always be in the INFINITIVE form.