The science of computer, _____rapid progress has been made in recent years, is the most important of all science.
Why do you want a new job ______ you’ve got such a good one already?
He was about to tell me the secret ______ someone patted him on the shoulder.
I was about to go out ______ the telephone rang.
We were swimming in the lake _______ the storm started.
She was walking down the road _______ she heard someone shouting for help.