单项选择。

There ______ a tree in front of the classroom last year, but there ______ now. [ ]

A. is, isn't

B. isn't, is

C. was, wasn't

D. was, isn't

（）可以用人民币现钞购汇购买外币旅行支票。

A.境内机构

B.驻华机构

C.境内居民个人

D.非居民个人在境内的合法人民币收入