/'swi:tn; `switn/
v
1 [I, Tn] (cause sth to) become sweet or sweeter （使某事物）变甜或变得更甜、芳香、悦耳、新鲜、可爱、温和等
*Fruit sweetens as it ripens. 水果成熟後就好吃了.
* I never sweeten my tea. 我喝茶从来不加糖.
* sweeten (the air in) a room, eg by opening a window 使房间里空气清新（如开窗）.
2 [Tn, Tn.p] ~ sb (up) (infml 口) make sb more agreeable, eg by offering gifts 使某人更随和（如向其送礼）
*I'll sweeten her up a bit by inviting her to the party. 我要邀请她参加聚会好让她随和一些.
3 (idm 习语) sugar/sweeten the pill => pill.

v
[I and T]
to make something sweeter, or become sweeter
　Sweeten the mixture with a little honey.
[T]alsosweeten sb⇔up
informal to try to persuade someone to do what you want, by giving them presents or money or promising them something
　a cash bonus to sweeten the deal
→sweetener
[T]literary
to make someone kinder, gentler etc
　Old age had not sweetened her.
→sweeten the pillatpill¹ (4)