calm: 平静冷静

There was an air of easy assurance and calm about him. 他表现出从容自信和冷静。

2、I kept telling myself to keep calm. 我不断叮嘱自己要保持冷静。

serene: 宁静安详

1、The sound was so serene that it seemed unearthly. 那种声音听起来是那么宁静，仿佛天外之音。