"We have to reply."
Translation:우리들이 대답해야 돼요.
The "들" is just for emphasis and does not necessarily include "you." https://medium.com/story-of-eggbun-education/korean-plural-marker-%EB%93%A4-deul-81c0c89ea9c5 With nouns relating to people, this redundancy is less unnatural, so 우리들 (we), 여러분들 (people) are fairly natural. https://korean.stackexchange.com/questions/426/when-must-i-may-i-use-the-plural-%EB%93%A4-on-nouns-pronouns