问题
单项选择题
不会造成风机出力降低的原因有（）。
A.转速变低
B.风机出口管道风门积杂物堵塞
C.入口管道风门或网罩积杂物堵塞
D.地脚螺栓松动
答案
参考答案：D
搜题请搜索小程序“爱下问搜题”
不会造成风机出力降低的原因有（）。
A.转速变低
B.风机出口管道风门积杂物堵塞
C.入口管道风门或网罩积杂物堵塞
D.地脚螺栓松动
参考答案：D
| 阅读下面短文，请根据上下文意思及方框中所给单词、短语的适当形式填空。 | |
The American explorer, R.E Bird, became the first man to fly over the South Pole in 1929. He 1 a lot of photographs during the flight but then he 2 difficulties. His plane could not get over the mountains so he 3 his men to throw out heavy food sacks. The plane then 4 the mountains and 5 without further trouble. |