( )21. Suddenly, they heard _____ whisper from the bushes behind _____ tree on the left.
A. a; the B. the; a C. a; a D. the; the
( )22. --- Whose book is it? --- I asked many people, but __________ knew.
A. everybody B. somebody C. nobody D. anybody
( )23. There are no buses. He has to ______there ______his bicycle.
A. go to; by B. go; by C. go to; on D. go; on
