People are often afraid of things they don't understand.

　　人往往對自己不懂的東西感到恐懼。

　　She doesn't understand the difference between right and wrong.

　　她不能明辨是非。

　　The committee has little or no understanding of the problem.

　　委員會對這個問題了解不多或根本不了解。

　　We need a clear understanding of the problems involved.

　　我們需要了解清楚所涉及的.各種問題。

　　This research has done much to advance our understanding of language learning.

　　這項研究大大提高了我們對語言學習的認識。