both、all有何區(qū)別
all全、都（三者以上），既可修飾可數(shù)名詞也可修飾不可數(shù)名詞。
All the books are useful to us.
All knowledge comes from practice.
all與否定詞not連用為“部分否定”，表示“不是所有的……都……”
I don't know all of them. 他們當(dāng)中我并不都認(rèn)識(shí)。
All don't agree with you.=Not all agree with you. 并非所有人都同意你。
both兩者都
You can take both of them.兩個(gè)你都可以拿去。
與否定詞連用表示“部分否定”。
I don't know both of them.他倆我并非都認(rèn)識(shí)。
both...and...雙方都……
He can both sing and dance.他能歌善舞。
both和all詞義辨析
1、both 只能與復(fù)數(shù)的可數(shù)名詞連用，與可數(shù)名詞的復(fù)數(shù)形式連用時(shí),both則指兩個(gè)。
You were both a prey to compulsions.你倆都太沖動(dòng)了。
2、all可與可數(shù)名詞的單、復(fù)數(shù)或不可數(shù)名詞連用，與可數(shù)名詞的復(fù)數(shù)形式連用時(shí), all指三個(gè)或三個(gè)以上。如：
All children deserve encouragement.所有的孩子都應(yīng)得到鼓勵(lì)。