1. You can't keep the typewriter until you have the typewriter, and you can't get it without asking to borrow it.
If you simply said to someone, "Can I keep your typewriter?", they might ask "What!? Have you stolen my typewriter?"
2. This is the normal way to say this in English.
S1 asks S2 what the matter is.
S1 asks S2 what the date is.
S1 asks S2 what the time is.
You can also say, S1 asks A2, "What is the matter?"
Where did you learn different?
Student or Learner