vt.

1. 使变甜；使变香
   Shall I sweeten your coffee?

   要不要我给你的咖啡加糖？

2. 降低（土壤、胃等的）酸性
3. 平息，抚慰；软化；减轻（痛苦等）
   A good meal sweetened his temper.

   一顿好饭使他心平气和了。

4. 【口】增加（担保物）；提高……的价值
5. 【俚】增加（扑克赌金）

vi.

1. 变甜；变香；变温和

v.

1. make or become sweet or sweeter.
2. make more agreeable or acceptable.
   ▸informal induce (someone) to be well disposed to oneself.