A distinction is often made between " positive " and " negative " eugenics.是什么意思？

A distinction is often made between " positive " and " negative " eugenics.

对 “ 积极 ” 优生学和 “ 消极 ” 优生学往往加以区分.

distinction

n. 区别，荣誉，特质，卓越；

例句
...her belief that scientists are trying to blur the distinction between 'how' and 'why' questions...
她认为科学家们试图模糊“如何”和“为什么”这两类问题之间的区别

is

vt.& vi. 是（be的三单形式；n. 存在；

例句
Bollinger 'RD' is a rare, highly prized wine.
博林格RD香槟是一种名贵的备受推崇的葡萄酒。

often

adv. 常常，经常，时常，再三；

例句
Genetic abnormalities are more often associated with faults in paternal DNA than in maternal DNA.
相对于母本DNA,基因畸变往往更多地与父本DNA上的缺陷相关。

made

adj. …制的，（人工）做成的，拼成的，虚构的，保证成功的；v. 使(make的过去式和过去分词)；

例句
Single people are treated as an aberration and made to pay a supplement.
独身者被当成异类，而且要付一笔额外的费用。

between

prep. 在…之间，私下，暗中，在…中任择其一，来往于…之间；adv. 当中，中间；

例句
How big is the abyss between what you think you are and what you actually are?
你对自己的认识和真实的你之间差别到底有多大？

positive

adj. 积极的，确实的，肯定的，[数]正的，[医]阳性的；n. 正面，正片，[语]原级形容词，[数]正量；

例句
Pupils should be helped to adopt a positive approach to the environment.
应帮助学生对环境采取积极的态度。

and

conj. 和，与，而且，于是，然后，因此；

例句
I spend a lot on expensive jewelry and clothing...
我花很多钱购买昂贵的首饰和衣服。

negative

adj. 消极的，否认的，[数]负的，[心]反抗性的，无预期结果的；n. 否定词语，否定的观点，消极性，[摄]底片；vt. 否定，拒绝；

例句
Being unemployed produces negative attitudes to work...
失业会产生对工作的消极态度。

eugenics

n. 优生学；

例句
An example of negative eugenics would be the attempt to eradicate a harmful recessive gene.
消极优生学的范例是试图破坏一种对人体有害的隐性基因.