What _____you ______ at 10:00 last night?
He doesn't tell me when he_______ . I'll telephone you as soon as he______.
——Who is knocking at the door?——It ______ Mr. Black, because he_______Washington.
In winter people usually keep flowers in their houses to ___them from the cold.
—— I feel tired and sleepy. ——Why not _______?
The picture shows us _______ in Nanjing in the past.