______ is known to us is that tobacco contains nicotine and other harmful products, so you should give up smoking.
According to the time table , the train for Beijing______ at seven o’clock in the evening .
Henry escaped ____ by admitting his mistake.
I first met Lisa three years ago. She _____ at a shop at the time.
He studies the subject _____.
Charles Babbage is generally considered ______ the first computer.