however,yet這兩個詞都含 “而、然而、卻” 等轉折的意思。
however:“然而、可是” 語氣較弱, 聯接也較少鬆弛。 因此常被用來插人句子中間。
例如:
You ask me to do the work I am afraid however that I amnot equal to it. “你請我做這事,然而,我恐怕不能勝任。”
yet:“而、然而、可是”,正式用語,讓步轉折的語氣較強烈,而且多指付出了努力,卻與預期結果或主觀打算相違背。常用短語:and yet 然而、可是:but yet 但是還…… 
如:His speech was almost unintellgible , ( and ) yet for some unknown reason I enjoyed it very much. “他的演講雖有些莫名其妙,但不知為何我卻非常願意 (喜歡) 聽。”
yet(用於疑問句和否定句)
還,尚,仍
如:He has not come yet.
他還沒有來.
She is yet a child.
她還是個孩子.
He was poor,yet happy.
他很窮,可是很快樂.
The driver's not yet conscious after the accident.
駕駛員在出事後,還沒有甦醒過來.
The doctors have not yet decided how the woman died.
醫生們尚未確定這位婦女的死因.
however
然而,但是
adv.無論如何,可是,仍然,究竟
conj.不管用何種方法,然而,可是
however 更像是“然而”yet比較長用來表達“但是”其實沒有什麼區別的除了however是比較長用在寫作方面,yet比較長用在對話溝通方面。