"The questions are welcome."
Translation:Die Fragen sind willkommen.
Asking questions in a big audience can be awkward for people not used to speak in public; a speaker or moderator of such an event would address people on a two step basis; the more general "Fragen sind willkommen" and if people need further encouragement use a personal address like "IHRE Fragen sind willkommen" wouldn´t she/he; :-)) to overcome such awkwardness some professors at university now even use an app that allows users to send their questions from their smartphones to the professor's smartphone who will then project these questions on a screen for everybody to read and answer ! Strange, isn´t it?
It doesn't have to be a big audience, though ;-) Some years ago in a seminar of our workgroup in which a few students were allowed to participate, my advisor ordered me in advance to ask at least two totally stupid questions, so that the students would feel more comfortable to ask their questions in turn. C'est une drole de vie! ;-)
Because "bist" is only used with du.
- Ich bin (I am)
- Du bist (you are)
- Er/sie/es ist (he/she/it is)
- Wir sind (we are)
- Ihr seid (y'all are)
- Sie sind (they are)
Here, we're taking about die Fragen, which is a plural thing in the third person (not me or you but they), so we use sind.
Just because English uses "are" for pretty much everything doesn't mean that German bist, sind and seid are interchangeable.
Yes, Duolingo doesn't look at your capitalization, you could have just as easily have written "the questions are welcome" without any capitals or punctuation and there would be no difference.
That being said, "Fragen" as a noun should always be capitalized in any German text.
Just as in English, verbs in German conjugate based on the subject of the sentence. So just as we say "I am" but "You are," German says:
- ich bin (I am)
- du bist (You (singular) are)
- er/sie/es ist (He/She/It is)
- wir sind (We are)
- ihr seid (You (plural) are)
- sie/Sie sind (They / You (formal) are)
"Die Fragen" is a "they" (third person plural), so we use "sind." If "du" were the subject, we would use "Du bist willkommen."
Here, "die Fragen" ( the questions ) are the subject. Fragen is third person plural, so the pronoun would be "sie" ( they ), and the conjugated form of sein for sie ( 3rd pl. ) is sind.
Seid corresponds with ihr, which is second person plural ( i.e. "you all" ). E.g. "Ihr seid willkommen" - You all are welcome.