"We have to get together soon!"
Translation:¡Tenemos que quedar pronto!
It's not obvious, but tenemos que quedarnos means "we have to stay."
I dont think that, in this case, "vernos" is reflexive with the 'tenemos que' as the first verb in the sentence". I think in that sense, the 'nos' on vernos is a direct object? With two verbs, I think you can put the D.O. in this case 'nos' on the end of the second verb. Does that make sense? Some other examples: "Yo quiero verlo" =I want to see it. "Quiero venderlo"= I want to sell it. "necesitas comprarlo?"= do you need to buy it. If Im wrong, pease tell me, but one of the issues I see over and over again has to do with reflexive verbs, so important to clairify. ojala que todo esta bien con usted.
Reflexive verbs can come after tener que. Example: Él tiene que ducharse ahora. This is a clear reflexive because se is used. Saying something like él tiene que ducharle ahora or él tiene que ducharlo ahora doesn't make any sense. Vernos is reflexive in this case, and it means "to see each other."
Well, Duo wanted you to use tener que instead of necesitar. There's a subtle difference. When you have to do something, it's usually a requirement imposed by someone else. But when you need to do something, it's intrinsic. Imposed by you. You need to breathe. But you have to get up to go to work or meet this other person soon.
Personally, I think Duo's use of 'get together' as a translation of 'quedar' was a bad idea (confusing at the very least). From the comments, I gather I'm not the only one struggling with this. Below is the closes translation I found on word reference:
"quedar vi (citarse)
arrange to meet, plan to meet, agree to meet v expr settle on v + prep Mi hija y sus amigas quedaron a las seis en el cine. My daughter and her friends arranged (or: planned) to meet at the cinema at 6 o'clock. ⓘ They settled on 7 o'clock for their dinner date."
Here are more uses of the word quedar, if anyone is interested. https://www.wordreference.com/es/en/translation.asp?spen=quedar
"Tienes" means "you have," while "tenemos" means "we have." Anyway, the reason you have to use the que is simply because it doesn't make sense without it. Whenever you say "have to" to mean "need" in English, use the tener que form in Spanish. "Tenemos quedar pronto" makes no sense in Spanish just like "We have get together soon" doesn't in English. Use "tener" to mean "to have" and "tener que" to mean "to have to."