如果三角形的一个外角不大于和它相邻的内角，那么这个三角形为[ ] A.锐角三角形

简述观光农业产业密切相关的政策。

据报道，美国宇航局的专家发明了“月球制氧机”，这种“月球制氧机”利用聚焦太阳能产生的高温使月球土壤发生化学反应制取氧气，据此可推测月球土壤中一定含有  [ ]

A. 氧元素

B. 氧气

C. 水

D. 氯酸钾

单位工程施工组织设计可以以下列选项中的（）为对象而编制。

A．一个机场

B．一个居住小区

C．一个烟囱

D．大量土石方工程

( )权属调查的特点是针对性强、任务急。

A．转让

B．变更

C．宗属

D．借让

In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.

Microwave communication uses (1) -frequency radio waves that travel in straightline sthrough the air. Because the waves cannot (2) with the curvature of the earth, they can be (3) only over short distance. Thus, microwave is a good (4) for sending data between buildings in a city or on a large college campus. For longer distances, the waves must be relayed by means of" dishes" or (5) . These can be installed on towers, highbuildings, and mountain tops.

4（）

A．material

B．equipment

C．medium

D．channel