"理想", 地道的英语怎么翻译?

理想: ideal
Relative explainations:
<it.> <ideality> <perfect> <perfection> <greatest nilpotent ideal>
Examples:
1. 他一直以为她是他儿子的理想伴侣。
He had always considered her an ideal companion for his son.
2. 这个国家的宪法体现了自由和平等的理想。
The country's constitution embodies the ideals of freedom and equality.
3. 这是一个出外野餐的理想日子。
It is an ideal day for a picnic.
4. 他正在寻找未来的妻子，但还没有找到理想人选。
He is looking for a wife but he hasn't found his ideal mate.
5. 他对人生抱有崇高的理想。
He has lofty ideals about life.
6. 她努力要实现她的理想。
She tries up to live up to her ideals.
7. 设备不理想，但我们已经尽了最大的努力。
The facilities were not ideal but we managed as best we could.
8. 在当代政治生活中, 理想主义根本行不通.
Idealism has no place in modern politics.

ideal gas
理想气体
ideal city
理想城市
ideal fluid
理想流体
moral ideal
道德理想
ideal constraint
理想约束
ideal soluti