This is a polite request, May I have your mobile number please? Your teacher's suggested correction, Can I get your mobile number please? is also acceptable, but not as polite. The situation will determine which of the two fits best. Context is everything.
As for your second question, try wording your sentences like this,
Ex: I was getting ready for work. I took a bath at 10 a.m., put on deodorant, ... .
Does that help?
Student or Learner