Translation:I doubt he would have helped the boys.
Your logic is good, but the subjunctive usage should be "one step back" regarding the main verb, thus "pretérito perfeito":
- Duvido que ele tenha ajudado = I doubt he has helped
- Duvidei que ele tivesse ajudado = I doubted he had helped
Present subjunctive is also acceptable, but with another meaning:
- Duvido que ele ajude = I doubt he will help / I doubt he helps
But in this sentence, what happens is another thing.
"Duvido" has the power of changing the verb from "futuro do pretérito" (conditional) to "pretérito imperfeito do subjuntivo"
So a sentence that would normally use "teria" uses "tivesse" instead:
- Duvido que ele teria ajudado se... = I doubt he would have helped if...
- Duvido que ele tivesse ajudado se... = I doubt he would have helped if...
With "duvido", you may see both sentences here and there. But if the word were "talvez" instead, you would see this "phenomenom" happen much more often , being "teria" very weird.
- Talvez ele "tivesse" (instead of "teria") ajudado = Maybe he would have helped. (In this case, since "talvez" carries no "tense", the other answer "Maybe he had helped" would also be ok.
Compare the usage of "pretérito perfeito" (tenha ajudado) with "pretérito imperfeito" (tivesse ajudado) when "duvido" is in present tense.
The first talks about actual past things (that may or not have happened)
The second talks about hypothetical things.
I think so....
Many colloquial variations appear:
- Duvido que ele tivesse ajudado
- Duvido que ele teria ajudado
- Duvido que ele tinha ajudado
- Duvido que ele ajudasse
- Duvido que ele ajudaria
- Duvido que ele ajudava
- Duvido que ele fosse ajudar
- Duvido que ele iria ajudar
- Duvido que ele ia ajudar
- Duvido que ele iria ter ajudado
- Duvido que ele ia ter adjudado
I'm still trying to find resources to clearly state whether the first two are both grammatical. But they sound good.
It's a VERY minor quibble, but "I doubt he will help" and "I doubt he helps" is very different (IMO) in English. If I translate my English thoughts to Portuguese, here's what I would say:
"Eu duvido que ele ajudará" = "I doubt he will help" as in, he hasn't helped yet, and I don't think he's going to help in the future
"Eu duvido que ele vai ajudar" = "I doubt he's going to help" as in, he hasn't helped yet and I don't think he's going to help now (or in the very near future)
"Eu duvido que ele ajude" = "I doubt he helps", as in I'm not sure if he has been helping them before now or right now, but I don't think he has been or is going to (in the very near future)"
I'd love it if someone could explain this!
Yes, they are different in English, however, they translate to the same sentence in Portuguese.
There are cases where the present subjunctive is used for future purposes. (Weirdly enough, the future subjunctive cannot be used in these cases - not sure if 100% of them)
The "duvido que" is one of these cases where you can't use the future subjunctive and have to use the present subjunctive to express future things. Nevertheless, the present subjunctive can still be used for present things.
Thus, "duvido que ele ajude" can take both translations, knowing they have different meanings.
For future purposes you can use "vá ajudar". Then it gets pretty clear you are talking about the future (although "vá" is still present subjunctive, the expression "vá entender" works as a phrasal future just like the indicative "vai entender").
Use "duvido que ajude" or "duvido que vá ajudar" for future purposes. Portuguese doesn't really differ near and distant future, you can use any of them.
Using "ajudará" or "vai ajudar" are equivalent to the previous two, they will be understood without much trouble, but then you are missing the subjunctive asked by "duvidar". It's quite common with some verbs, but can get weird sometimes.
Use "ajude" or "esteja ajudando" if you are talking about the present. You don't know if he currently helps, or if he is helping right now.
The non subjunctive option for these last two sound ugly and I'd avoid them.
- "espero que entenda"
It's the exact same case:
- The verb "esperar" asks for the subjunctive. (But different from duvidar, it doesn't sound good at all with the indicative "entenderei")
- Here too, we use the present subjunctive "entenda" (or "vá entender") for future purposes.
Optionally, "esperar" accepts the infinitive too:
- "espero entender". (coincidentally, the infinitive has the same spelling as the future subjunctive, but it's indeed infinitive -- that can be detected using irregular verbs such as "ir": espero ir)
Non related hint:
We can't drop "that" conjunction in Portuguese =/
- Devo admitir "que (that)" não entendo.....
According to "textbook" grammar (which contradicts the grammar in DL's sentence), duvidar in the present tense is followed by either the present subjunctive or the present perfect subjunctive:
Duvido que ele ajude.
Duvido que ele tenha ajudado.
Danmoller (above) lists eleven colloquial variations that you will hear in Brazil.
Para mim, também soa mais natural =)
A situação não ocorreu. Seria algo do tipo "E se...?" (What if...?)
Se ele encontrasse os filhos novamente, duvido que ele teria ajudado os meninos. (hipóstese, pouco provável)
Se ele encontrar os filhos novamente, duvido que ele ajude os meninos. (maior probabilidade de ocorrer)
Danmoller (above) gave many variants of what Brazilians would say, most being colloquial. Just as it is difficult for us to determine correct usage, it's also difficult for most Brazilians. Portuguese is diglossic: the [complicated] written grammar is distinct from spoken grammar. Brazilian linguist Mário Perini has good news and bad news about Portuguese:
"Para quem gosta de certeza e segurança tenho más noticias, a gramática não está pronta. Para quem gosta de desafios, tenho boas notícias: a gramática não está pronta. Um mundo de questões e problemas continua sem solução, à espera de novas ideias, novas teorias, novas análises, novas cabeças". (Mário A Perini, Phd, 2003).