21. —Look! What’s in the tree?
—_______ bird, I think.
A. 不填 B. A C. An D. The
22. —Can you make ______understood in English? —Yes, I can.
A. yourself B. you C. yours D. your
23. There _________ quite a lot of trees on the hill.
A. were used to being B. had C. used to have D. used to be
