deep contemplation
moment of contemplation
in contemplation of
silent contemplation
A: Why are you so quiet today?
A：你今天怎么这么安静？
B: I am just lost in contemplation.
B：我只是陷入了沉思。
1) 沉思或冥想
2) 仔细的思考
3) 深思熟虑
1. 沉思，冥想
noun
1. The action of thinking about something carefully and deeply for a long time.
Synonym: meditation, reflection, thought