"He reads from his book."
Translation:वह अपनी किताब से पढ़ता है।
उसका, उसकी, उसके mean his/her when the person the item(s) belong to is not the subject. अपना, अपनी, अपने are reflexive pronouns and literally mean "own"; so they are used when the object belongs to the subject. ie I read my (own) book मैं अपनी किताब पढ़ता हूँ. He eats his (own) apple वह अपना सेब खाता है. You live in your (own) house तुम अपने घर में रहता हो. I hope that helps.
One wouldn't. Nouns ending -ii are mostly feminine, and -a mostly masculine, but there are exceptions (mostly if not all where they're 'loan words' from e.g. Sanskrit or English), but with other endings I don't think there's even a rough rule of thumb like that.
Hardly a problem unique to Hindi though!
But the Tips & Notes section for Basics 1 (as well as other sources such as https://en.wikibooks.org/wiki/Hindi_Lessons/Lesson_3) state that यह can be used for he/she as well.
I'm confused by this too - I was taught that it was a question of proximity: that yah can mean he/she/it/this (for nearby subjects) and vah can mean he/she/it/that (for more distant subjects). But it seems to be exclusively vah for he/she here, and a few people in the comments seem to confirm that.
In another sentence in the lesson, "Julia goes to her sister's house", since 'her sister' was Feminine, oblique case was 'Apni'
Here, since 'book' is Feminine, oblique case is 'Apni'.
My question here - Comparing the sentences, 1. Where does Julia go? - her sister's - house 2. From where does he read? - his - book
In first sentence the oblique transformation was because of first part(her sister), and in second the oblique transformation was because of second part (book). What's the rule here?