—Have you finished your project, Alice? —I’m afraid I forgot about it.
The president promised to keep all the board members _____ of how the negotiations were going on.
______ chemistry is a branch of chemistry.
More and more high-rise buildings have been built in big cities ______ space.
---We haven’t seen each other for ages. ---No, I don’t remember how many years ago _______ I last saw you.
We are still at the airport.If it weren’t for the delayed flight, we _______ the concert right now.