Gerundio is used often in dependent clauses where it has specific functions.
Temporal clause: "Camminando, pensavo a Giovanni (While I was walking I thought about John)". Here "camminando" can also be written "mentre camminavo" or "mentre stavo camminando".
Hypothetical clause: "Volendo, possiamo andare insieme (if we want we can go together)".
Causal clause: "Partendo domani ti ho comprato un regalo (as I am leaving tomorrow I have bought you a present". here "partendo" can be written "poiche' parto" or "dal momento che parto" or "siccome parto".
Concessive clause: "Pur studiando ogni giorno, non riesco ad imparare l'italiano (even if I study every day I can't learn italian)". Here "pur studiando can be written "anche se studio" or "sebbene studi" or benche' studi".
modal clause: "Ho raggiunto il faro camminando lungo la riva (I reached the lighthouse by walking along the shore)".
No, Germanlehrerlsu is correct. The subject of the participle and the subject of the main clause are the same. To be sure, whether in this case we say 'if you want' or 'if we want' makes little difference to the meaning, but in other cases it might. So stick with 'if we want''.
You ask why the subjects "have to be" the same. The answer is that that is how Italian speakers use this construction.
Could it have been otherwise? Could it be otherwise in some parallel universe that we do not have access to? Perhaps.
But the reason the "rule" is what it is is that native speakers of Italian (or at least the majority of educated ones) use the construction in the way the "rule" describes.
Teresinha: see my -- and other -- comments above. When using a gerund, its subject is the same as that of the following clause. If there were a diffentent subject in the introductory clause, then a conjugated verb form would be used. So if you meant, "If YOU want, WE..." then you'd see Se vuoi, possiamo.. I believe that's correct and leave it for others more knowledgeable to confirm or correct.
This example of causal clause using gerund (partendo domani ti ho comprato un regalo) is not idiomatic in Italian. Better examples:
- Non potendo volare, l'uccello rimane dov'è.
- Essendo domenica, i negozi non erano aperti.
- Essendo straniera, non me l'aspettavo.
- Partendo domani, ti farò piangere.
I am currently in Italy and I have asked an Italian friend who is a language teacher about our problem. She said that volendo can be used with you, we, and even they (sentence different). It seems the best explanation is provided by pmm122 by translating volendo into willing. Even though it would be ackward in english it still conveys the meaning most clearly and lets us understand what is being said. Never mind the correct English translation, the object is to understand italian unless we all want to be professional interpreters. Haggling about the correct English translation is counterproductive and will not help us learn Italian. Volendo=willing is the best explanation. It would be great if some native Italians would comment on our difficulties in understanding Italian and guide us.
Apart from the change in word order, volere means "to want" rather than "to like". So even though an English speaker might use "like" in this context this is not an accurate translation of volendo and so I presume that it has not been included in the list of accepted translations for that reason.
A couple of times, I've used "andarci" for this (because a place isn't specified, and the verb 'andare' feels like it needs some sort of location). Duolingo doesn't accept it, but I'd love to find out what a native speaker thinks. Wrong? Right? Sounds fine but means something different? Grazie in anticipo.
I think it has been rejected because it requires "we" as the subject of the gerund. The general rule is that the subject performing the action that is described in the gerund must be the same as that of the main clause. There are exceptions but in these cases the different subject is clearly stated or implied, which is not the case here.
I think that is a reasonable, if non-literal, translation as the speaker would not be suggesting it if he/she were not in favour of it. So, even though Italian grammar rules apparently say that the condition implied by the gerundio is that "we" must both want to go, it effectively just leaves the implied condition of the second person also wanting to go.
To me the most usual is gerund as in -ing participle, to make a continuous tense in English. Quite important the other cases though. But i am wondering if it is just a convenient way to say the same more analytical in these cases. For us, the learners from a different language background this way is easier. Gerund is not the same in all languages that already use it. In my native language is used with an adverbial use mostly, temporal use, in English is a noun actually.
I have met just only a few sentences like this one.