她在咖啡里加了一些糖来增加甜味。

She ___sweetens her coffee with some sugar.

房东降低了租金并免除了押金，让租房条件更具吸引力。

The landlord ___sweetened the rental agreement by lowering the rent and waiving the deposit.

她精心准备的惊喜让他的心情变得愉悦起来。

Her carefully planned surprise ___sweetened his mood instantly.