从下列各题所给的A、B、C、D四个选项中,选择可以填入空白处的最佳选项。
( )19.-Is this ______ classroom?
-No, it’s theirs.
A. we B. us C. our D. ours
( )20.- What did you do ______ Sunday morning?
-We just stayed at home and watched TV.
A. on B. in C. at D. for
( )21.My parents ______ both teachers. They teach in the same school
( )19.-Is this ______ classroom?
-No, it’s theirs.
A. we B. us C. our D. ours
( )20.- What did you do ______ Sunday morning?
-We just stayed at home and watched TV.
A. on B. in C. at D. for
( )21.My parents ______ both teachers. They teach in the same school