I found _____ very difficult to learn  maths  well.

— Can I use your notebook computer this afternoon? ________ is under repair.— No problem. 

When she was walking in the street, she met a friend of _______.

My son want a pet rabbit for long, but I have no time to buy ______ for him.

I’m sorry that I can’t pass you any salt because there is_________ in the bottle.