— The bag is too heavy to carry. What’s in it?— Oh, I_______ it_______ books.
--- Listen ! Who _______in the room? ---Let’s go and see.
He is taking ______ now.
They are having _______ dinner at home.
----How are you going, buddy? ----________. A little busy, though.
Scientists from different countries are trying to_______ a good way to solve the energy problem.