He would resurrect his old eager ambitions and pursue them without faltering.
Those solemn but sweet organ notes had set up a revolution in him.
请问老师句中的but怎么样理解？什么词性，使用方法，和含义？
solemn but sweet：庄严而悦耳的
but 是连词，跟 and 有哪些用途一样。意思上表示两个事物或性质上的相对或对立。比如：
He is a serious but lively leader. 他是一个严肃而活泼的领导人。
“活泼” 和 “严肃”，意思相对。