2 sentences for 定下 (dìng​xià — set)

1. 我们还没定下结婚的日子。

   wǒ​men hái méi dìng​xià jié​hūn de rì​zi.

   We haven't set a date for the wedding yet.

   Source: Dong Chinese Dictionary

2. 经理为这次会议定下了基调。

   jīng​lǐ wèi zhè cì huì​yì dìng​xià le jī​diào.

   The manager set the tone for the meeting.

   Source: Dong Chinese Dictionary