—When did your brother begin to show his interest in medicine.—It was a Saturday _____ he noticed his classmate experimenting on a frog in the lab.
This is the very information _______ we can learn what is selling best in the market. .
All _____ can be done has already been done.
The girl ______in red is a successful writer, who _______ Tom last month.
Mr. Smith doesn’t believe that his daughter can work out the problem that easily,_____?
It is said that Tom hasn’t passed the driving test, but, ______ he is a little too young.