明白用英文怎么表达？?

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

人往往对自己不懂的东西感到恐惧。

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.

委员会对这个问题了解不多或根本不了解。

We need a clear understanding of the problems involved.

我们需要了解清楚所涉及的`各种问题。

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

这项研究大大提高了我们对语言学习的认识。