Mr. Sawyer started his career at Stanford University, _____ he became Professor of Physics in 2002.
Thank you for giving me a hand. I ______ in the experiment without your valuable help.
This cake is very sweet. You _____ a lot of sugar in it.
He paid for a seat, when he ______ have entered free.
Helen ______ go on the trip with us, but she isn’t quite sure yet.
— Tom is never late for work. Why is he absent today ? — Something _______ to him.