肉眼的英文：
naked eye
layman's eyes

参考例句：

Observe with an unaided eye
以肉眼观察

That comet is invisible to the unaided eye.
那颗彗星只用肉眼是看不到的。

Invisible to the naked eye
肉眼看不见的

Bacteria are too small to see with the naked eye.
"细菌太小,肉眼看不见。"

This star is not visible to the naked eye.
这颗星肉眼看不见.

Dull, stupid
肉眼无珠

Germs are invisible to the naked eye.
细菌是肉眼所看不见的。

These tiny creatures are hardly visible to the naked eyes.
这些微小的生物肉眼几乎看不见。

Most cells are too small to be detected by the unaided human eyes
绝大多数细胞都很小，肉眼看不到。

The crane is a small constellation that can be viewed with the naked eye.
天鹤座是用肉眼就可以看见的一个小星座。

naked是什么意思：
adj. 裸体的，裸露的；无装饰的，无保护的；坦白的，率直的

You're a naked speaker, sir.
你是一位说话坦白的人，先生。

It is considered an offense to shower naked.
裸体淋浴被视为犯法。

A bare assertion is not necessarily the naked truth.
坦率的主张未必就是坦白的事实。

eye是什么意思：
n. 眼睛；视力；眼光；见解，观点
v. 注视，细看

An eye for an eye and a tooth for a tooth
以眼还眼,以牙还牙

It is a mere coincidence that they see eye to eye on this point.
他们在这一点上见解一致完全是巧合。

I think we see eye to eye on that subject.
我认为我们在那个问题上看法一致。

layman是什么意思：
n. 门外汉，外行人，普通教徒

Quercus, or, to the uninformed layman, the oak..
栎属乔木,亦即外行人所谓的橡树....

He is only a layman authorized to read sermons.
他就是一个被授权布道的普通教徒。

The layman is generally more concerned with their possible unethical uses
外行人通常担心它们可能产生非道德的用途。