Verb. To make something whiter, or to become whiter.

Verb動詞。To make something whiter使某個東西變白 or或者 to become whiter自己變白

It works both ways with no change of form: "this toothpaste whitens teeth" (someone acts on something) and "the sky whitened as the sun rose" (something changes by itself).

It它 works both ways兩種用法都可以 with no change of form形式都不變 "this toothpaste whitens teeth"「this toothpaste whitens teeth」（這是某人讓某個東西發生變化：這牙膏讓牙齒變白） "the sky whitened as the sun rose"「the sky whitened as the sun rose」（這是東西自己變化：太陽升起時天空變白了）

Where you meet it most is in beauty and cleaning: whiten your teeth, whiten your clothes, whitening cream, teeth-whitening treatment. In Taiwan and much of Asia, 美白 skincare is a huge market, so 'whitening' is the word all over those English labels.

Where you meet it most你最常遇到它的地方 is in beauty and cleaning是美容和清潔類 whiten your teeth美白你的牙齒 whiten your clothes讓你的衣服變白 whitening cream美白霜 teeth-whitening treatment牙齒美白療程。In Taiwan and much of Asia在台灣和亞洲大部分地方 美白skincare美白保養品 is a huge market是個很大的市場 so所以 'whitening''whitening' is the word all over those English labels是那些英文標籤上到處都看得到的字

It is also used of faces and skin losing colour from shock, fear or cold: "his face whitened when he heard the news". This is a bit literary; in ordinary speech people say went white or turned pale.

It它 is also used of faces and skin也用在臉和皮膚 losing colour from shock, fear or cold因為驚嚇、害怕或寒冷而失去血色 "his face whitened when he heard the news"「his face whitened when he heard the news」（他聽到消息時臉色發白）。This is a bit literary這用法有點文學性 in ordinary speech在一般口語裡 people人們 say went white or turned pale會說went white或turned pale

A note on which word to choose. English usually prefers turn white or go white for something changing on its own — "her hair turned white", not usually "her hair whitened". Whiten sounds most natural when someone does it on purpose to something, or in writing.

A note選哪個字 on which word to choose有一點要注意。English英文 usually prefers通常比較喜歡用 turn white or go whiteturn white或go white for something changing on its own來表示東西自己發生的變化 "her hair turned white"「her hair turned white」 not usually而不常說 "her hair whitened"「her hair whitened」。Whitenwhiten sounds most natural聽起來最自然 when someone does it on purpose to something是有人刻意對某個東西做這件事的時候 or者或 in writing在書面語裡

And be careful with people: to whiten skin is a loaded phrase, tied to real and painful history about skin colour, so in most conversations use lighten or brighten instead unless you mean the cosmetic product.

And而且 be careful with people用在人身上要小心 to whiten skin使皮膚變白 is a loaded phrase是個帶有負擔的說法 tied to real and painful history about skin colour跟膚色相關的真實、痛苦的歷史牽連在一起 so所以 in most conversations在大多數對話裡 use lighten or brighten instead改用lighten或brighten unless you mean the cosmetic product除非你指的是化妝品