《芝加哥国际民用航空公约》所指的国家航空器是()
A.国家所有的航空器
B.国家经营的航空器
C.在该国登记的航空器
D.用于军事、警察等部门执行公务的航空器
参考答案:D
—What are we supposed to do first if we want to develop our village?
—Lots of new roads _____, I think. [ ]
A. must built
B. can build
C. can be built
D. must be built
礼貌待人有利于构建和谐社会。