The man is a cleaner the zoo.[ ]
A. on
B. to
C. about
D. at
答案：D
______是产业间适应激烈竞争的一种自救方式，对于重新搭建和稳定产业链、保证上下游产业间合理利益，维护产业安全具有重要作用。
A．知识产权
B．技术壁垒
C．贸易壁垒
D．战略协作
To enjoy the scenery, Sara would spend long hours on the train ____ travel by air. [ ]
A. as to
B. other than
C. instead of
D. rather than
