動詞 expatiate:

1. add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing
   同義詞：elaborate, lucubrate, exposit, enlarge, flesh out, expand, expound, dilate

1. His deep knowledge of the historical background enabled him to expatiate upon the significance of the movement.
   他對于歷史背景的深刻了解使他能夠詳細闡述這場運動的意義。
2. The chairman expatiated for two hours on his plans for the company.
   董事長用兩小時闡述了公司的規(guī)劃。

ex.pa.ti.ate

v.intr.（不及物動詞）
ex.pa.ti.at.ed,ex.pa.ti.at.ing,ex.pa.ti.ates
To speak or write at length:
詳述：詳細地敘述或描寫：
例句：
expatiated on the subject until everyone was bored.
詳細地描寫那個物體直到每個人都厭煩了

To wander freely.
漫游：自由地到處走動

來源：
Latin expati3ro expati3t-
拉丁語 expati3ro expati3t-
ex- [ex-]
ex- [前綴，表.出自….]
spati3ro [to spread] from spatium [space]
spati3ro [使散開] 源自 spatium [空間]

【引伸】
expa.tia.tion
n.（名詞）