Feedback is like gold dust when you're learning a language.

学习语言时，反馈就像金粉一样。

A textbook in astrophysics is like gold dust.

天体物理学教科书就像金粉。

Now we had an account from a Wren who was based here in Dover called Doreen, and her account says that skincare became really hard to get hold of during the war, it was like gold dust.

现在我们有一个来自多佛的 WRNS 的阐述，她叫多琳，她说护肤品在战争期间变得非常难获得，就像金粉一样。