—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.
My uncle has a lot of books, _______ are about computer science and technology.
He, along with his brothers, ______ how serious the situation is.
This is the factory ________ we visited last Monday.
______ you have finished your work, you ought to have a good rest.
All of her time was devoted to_______ her homework, so she had no time to have fun.