Major changes in tractor design include the power takeoff, the all-purpose or tricycle-typetractor, which enabled farmers to cultivate planted crops mechanically;
The article has expounded a new type of tractor, called it as new conception tractor.
本文论及的是一种新型拖拉机，作者称之为新概念拖拉机。
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A new type of random program constant amplitude load spectrum is introduced, which is used in laboratory simulation test and life prediction of tractor components under random loading.