We stop ___________ when our teacher comes in.A. playing B. to play C. play
– How long has Robot _________ ? – Since2004.
Great changes _________ in Nanjing since the1990s.
My mother _________ a history teacher.
–Have you finished your homework? – _________ . Just half of it. How about you?
– _________ you ________ your lost football? _Yes, I have. I _________ it an hour ago.