——There must be a dozen pens in this house but I can never find one when I need one.——Keep looking. is sure to turn up.
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.