It had asymmetric flight feathers not only on the forelimb, but on the hindlimb as well.

它已非对称飞羽不仅对前肢，但对后肢以及。

youdao

University of Washington scientists say it depends on how fast you can replace your flight feathers when you molt.

来自华盛顿大学的科学家们说，这取决于在换羽的时候，你更换飞行羽毛的速度。

youdao

Small birds molt once or twice a year, and they replace their 9 or 10 primary flight feathers a few at a time over the course of a few weeks.

小型鸟类一年进行一到两次换羽，在换羽期间，它们一次会替换掉9到10根左右的飞羽，而这个过程将持续几周时间。

youdao

But Dr Dial wanted to be sure, so he compared the accomplishments of normal partridges with birds that had their wing feathers clipped to half their normal surface area, and to even less fortunate fowl whose main flight feathers were entirely plucked.

ECONOMIST: Birds that don't fly may be using their wings to run uphill

The Dromaeosaur is more primitive than birds, suggesting that feathers developed before flight.

BBC: Dinosaur was covered in feathers

"We now know that feathers did not originate as flight structures, " said Professor Benton.

BBC: Dinosaur had ginger feathers