But they also had more flexible shoulder joints; broad, flat rib cages; and a shorter spine.

但他们也有更灵活的肩关节； 宽而扁平的肋骨； 和较短的脊椎。

And while parrots' beaks are rigid, they have very flexible jaw joints, giving them a lot of control over how wide and how quickly they open their beaks.

虽然鹦鹉的喙是僵硬的，但其下颌关节十分灵活，这让它们可以很好地控制张开喙的宽度和速度。