After ________ dinner, Stephanie likes to play ________ guitar for a while in the garden. A. a; a B. 不填; the C. the; a D; 不填;不填
The head teacher comes to the classroom ______ to see if the students are quiet.
I’ve been playing the piano for four hours and I am ________ it.
Look, a demonstration ________ on Main Street.
What he has done has a bad effect ________ the children.
Zhongguancun was ________ as a special economic zone in the late 1990s.