--- Mum, _______ is my friend, Jim. --- Nice to meet you.
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.