General broad suggestions/fixes and Thanks!!
I would like to first say thanks to all who contributed to this course! I know a lot of learners are pointing out bugs, problems, and errors all of the place, but I can appreciate that a lot of time and effort went in to making this beta course. I, for one, am extremely grateful for all the work!
After completing quite a bit of the Chinese course, I have some general translation suggestions:
"They" = 他们 or 她们
"week" including days of the week should accept 周，礼拜, and 星期
一点儿，哪儿，这儿，那儿 and other additions of the 儿 for the Northern accent are fine, but the alternative forms of 一点，哪里，这里，那里 and others should also be accepted
"You" = 你 or 你们
“你们” = you or you guys or (if you are from certain parts of the US) you all or y'all.
的 between the subject pronoun and family members seems to be arbitrary at the moment. I think, though I'm not a native mandarin speaker, the most common is to omit the 的 when speaking.
The use of the 了 particle. There have been several instances where its use seems arbitrary. And it seems like, at least to me, that there are several sentences where Duolingo omits the 了 but I have heard native speakers use it in similar, if not identical, sentences.
Finally, (for now at least) the distinctions between 想，想要，要，and 需要 are not clear and seem arbitrary. Sometimes 想 is translated as "would like" and other times as "want". Sometimes 要 is translated as "want" and sometimes as "have to" and sometimes as "need (to)". Sometimes 需要 is translated as "need (to)" and sometimes as "must". Again, I'm not a native speaker, but this is the way it seems to me.