沉静的英文：
peaceful
quiet
calm

参考例句：

She saw only that he was quiet and unobtrusive, and she liked him for it
她只知道他沉静而谦逊，并因此而喜欢上他。

She was in a placid mood.
她心情沉静。

He was clever and cheerful and brave in his actions,but mild and quiet in his ways.
他很聪明，乐观，行动勇敢，举止文雅沉静。

The swift and indifferent placidity of that look troubled me
那一扫而过的冷漠沉静的目光使我深感不安。

He discovered that the mountains at night were magnificent, mysterious and quiet.
他发现了夜山的"雄奇、黑密、幽深、沉静"

He stood in the doorway, listening to her quiet, regular breathing.
他站在走道里，听着她那沉静而规律的呼吸声。

Ever since his recovery he has been placidly frail, yet capable of surprising endurance
自从他病愈之后，就一直沉静而虚弱，却有惊人的耐力。

After a pause the audience Broke into cheers.
短暂的沉静后，听众突然爆发出欢呼声

At twilight, the stillness was broken by the sound of hooves, clattering on the paved courtyard.
在一个黄昏，沉静被庭院上一阵清脆的马蹄声所打破。

Through the silent night I hear the returning vagrant hopes of the morning knock at my heart.
透过沉静的黑夜我听到早晨流浪的希望回来了，敲着我的心。

peaceful是什么意思：
adj. 和平的；爱好和平的；平静的

The doctor was at peace.
博士生活得很安宁。

a book the length of `War and Peace'
像《战争与和平》篇幅那样长的书

Be vigilant in peace time.
居安思危。

quiet是什么意思：
adj. 安静的；秘密的；素净的
n. 寂静；安稳
v. 使平静；抚慰；平静下来

It was quiet in the streets, awesomely quiet.
街上安静得让人有些害怕。

quiet diplomacy
静默外交; 悄悄的外交; 秘密外交

Quietness is best
宁静最好

calm是什么意思：
adj. （水面）平静的，（天气）无风的；镇定的，沉着的，宁静的
n. 平静；无风；镇定；安静
v. 使平静；使镇定；安静下来

The tempest calmed.
暴风雨停息了。

You must keep calm in an emergency.
在紧急关头要保持镇静。

calm zone of Cancer
北半球副热带无风带