... my foot down ;put our foot down ;put their foot down ;put your foot down 采取手段 take means ;taken means ;took means 采取措施 adopt measures ;take a step ;take measure ;take measures ;take precautions ;take steps ;taken measures ;taken ...
The best guesses are that feathers evolved either for insulation (as fur did in mammals) or for display, and that natural selection took advantage by turning them into a means of transport.