When walking down the street, I came across David, when I _____ for years.
didn't see
haven't seen
hadn't seen
wouldn't see
UN Secretary-General Ban Ki-moon left for Pakistan this morning, his assistant _________ him there this Friday.
______, the conference began.
Zhang Ziyi and Wang Feng, both of them ______ in the media spotlight, get romantically involved.
Entering the bookstore, I noticed a girl _______ against the window, with her eyes_____ on her book in hand.
In the middle of February, the weather__favorable for work, the workers began to repair and secure the dam of the river.