The door opened and in________.
—I thought you ______ for vacation tomorrow. —I had planned to, but I have a very important meeting to attend tomorrow.
The development of industry has been ____gradual process throughout _____ human existence, from stone tools to modern technology.
The police are trying to find out the ____ of the woman killed in the traffic accident.
---I got a rise in salary! ---_____________.
He went home for lunch____ the clock struck twelve.