fairly/really/very/extremely

當 fairly, very, extremely 作副詞用時，它們都可作加重語氣 [ 十分; 非常] 的解釋，
但它們的[ 十分; 非常] 程度各不同，
fairly 是 較低層次的
very 是一般的
extremely 是極端的 She is a fairly good dancer.
她是一個相當不錯的舞蹈演員。

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He walked very fast. 他走得非常快。 It's very cold today. 今天很冷。
============================We got on extremely well.
我們相處得極好。I am extremely sorry. 我非常抱歉。This is an extremely difficult task.
這是一項極其困難的任務。=====================
really 當really 作副詞用時，
它是可作加重語氣 [確實] 的解釋， Did she really say that?
她確實那麼說了? It's really cold today.
今天確實 很冷。