21. If we sit in____front of the bus, we’ll have a better view(视野).
A. the B.不填 C. a D. an
22. --What are you going to do next？
--I am going to ____ a bus.
A. waiting for B. waiting C. wait for D. wait
23. --- Who teaches ________ Chinese
--- Mr. Wu does.
A. they B. their C .them D your
