"This is his mom."
Translation:זאת אמא שלו.
What about: "זאת הבת שלו" Sounds very natural to me as a Native speaker. If think it only applies for אמא and אבא. It works for all other family members.
It's because אמא already has the definite article (the), because it's an Aramaic word and Aramaic puts the definite article at the end rather than the beginning of the word. So, it doesn't sound natural because Jews have been using Aramaic and Hebrew side-by-side for eons. The Palestinian Talmud (Yerushalmi), for instance, has sentences in which there is both Hebrew and Aramaic, sometimes almost mixed. Some of the Aramaic words survived in Hebrew, the most common of which are אמא and אבא. So if one puts האמא it is redundant. It is the equivalent of saying "the" twice in English. I just put זאת אמו and it passed fine. But if one puts זאת אמא שלו it would be fine, too and maybe even a little bit more correct. I'm not a native speaker. The Jews picked up Aramaic in the Babylonian Exile and so it was their language even more so than Hebrew for the period ca. 350 BCE-600 CE. Hebrew was the language of prestige and of the sacred text, so it was always kept alive by the rabbis, but the regular people spoke either Aramaic or Greek in the period ca. 350 BCE-600 CE (until the Muslim conquest).
Here's every Hebrew tip & note broken up by skill: https://www.docdroid.net/JnfmyEV/tipsnotesbackup.pdf
Sorry to bother you, but maybe someone knows what I should do. Someone wrote we should look in the reading material for further grammar info. But I don't have this reading material, or the Tips&Notes section. I searched the whole app. So I thought it is missing here and wanted to look on the internet page. But to log in wasn't possible because I don't know which password I used and there is no chance to find out because it is nowhere. I even changed it, but I couldn't log in. So I won't ever be able to use duolingo properly and learn hebrew better.
Unfortunately, the tips and notes are only available on the desktop version. But you should be able to use the same log in info for it!