The ideas were not new. Their development had proceeded steadily since the war...是什么意思？

The ideas were not new. Their development had proceeded steadily since the war...

这些并不是什么新思想，自从战争开始就一直稳定地发展演变。

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

ideas

总念；

例句
An important set of ideas have been advanced by the biologist Rupert Sheldrake.
生物学家鲁珀特·谢尔德雷克已提出了一整套重要的观点。

were

be的过去时复数和第二人称单数形式，有时代替 was,用于条件从句、动词 wish 之后等；

例句
Shops, houses, and vehicles were set ablaze.
店铺、房子和车辆全都陷于火海。

not

adv. 不，[用以表示否定、否认、拒绝、禁止等]不是，几乎不，未必，没有[用于否定后面的词或短语]；

例句
It became very clear that the incident was not just an aberration, it was not just a single incident.
事实已经很清楚，这件事不是偶发的，它并不是一起孤立的事件。

new

adj. 新的，崭新的，新鲜的，新到的，现代的，初次（听到）的；adv. 新近，最近；

例句
When I listen to her play I can hear a new Nigel Kennedy.
从她的演奏中我听出了新一代的奈杰尔·肯尼迪。

their

pron. 他（她，它）们的，在提及性别不详的人时，用以代替 him 或 her；

例句
Their permissiveness toward their children reflects the wild abandon of their own lives.
他们对孩子的放任折射出他们自身生活的放浪形骸。

development

n. 发展，进化，被发展的状态，新生事物，新产品，开发区；

例句
The 1985 federal budget allocated $7.3 billion for development programmes...
1985年的联邦预算将73亿美元拨给了开发项目。

had

v. 有（ have的过去式和过去分词 ），（亲属关系中）接受，拿，买到；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

proceeded

v. 进行( proceed的过去式和过去分词 )，前进，（沿特定路线）行进，（尤指打断后）继续说；

例句
He asked for ice for his whiskey and proceeded to get drunk.
他要求给他的威士忌里面加冰，接着喝得大醉。

steadily

adv. 稳定地，持续地，稳固地；

例句
...a theory that is steadily gaining acceptance...
逐步得到承认的理论

since

prep. 从…以来，自从…之后，自从；adv. 以后，此后，后来，（距今几年）以前，（从那时候起几年）以前；conj. 自从…以来，自从…的时候起，既然，因为；

例句
Janet had been abused by her father since she was eleven.
珍妮特从11岁起就遭受父亲虐待。

war

n. 战争，战争期间，斗争，论战；vi. 进行战斗，作战，同…处于交战状态；

例句
The war has aggravated an acute economic crisis...
战争加剧了原本已很严重的经济危机。