- 搜标题
- 搜题干
- 搜选项
单项选择题
Which of the following modern farm tools is NOT developed based on push sickle? A.
Which of the following modern farm tools is NOT developed based on push sickle? A.
Reaper. B.
Reaper-binder. C.
Combine-harvester. D.
Grain drill.
、尺寸因数
、表面质量因数
。它们的值域为（ ）。
，
，
< 1，
，
< 1，
，
，
可大于1，也可小于1
