我的疑问是 Isnt it a pleasure to have peace of mind whild reading?中的 have peace of mind为什么have 后面不用加a?

pleasure在这是可数名词意思是an activity or experience that you enjoy very much即"非常喜欢享受的一种活动或一次经历“pleasure作为不可数名词时候意思是the feeling of happiness,enjoyment,or satisfaction th...