We are waiting___ the bus stop(车站).[ ]

Thank you very much.　-You are welcome. I was _____ glad to help.

This math question is too difficult. Can you help me?

There is still a copy of this book in the library. Will you go and borrow _________? –No, I will buyin the bookstore.

Although it seemed to be ______ uncomfortable experience, he still found it ______ fun to learn diving.