I’ m sorry, I mistook you ___ your sister ___ mistake.
Don’t enter the office unless _______.
Can you find a sentence situation _______ this phrase can be used? A. where B. when C. which D. that
Trust him please! When he _______ reading it, he will return the book to you on time.
He is my father and I know he will forgive me for _______ I have done.
Charles is believed_______ the floor yesterday; he is always helping others silently.