4 sentences

1. 她心情很好，嘴里哼着轻快的调子。

   tā xīn​qíng hěn hǎo, zuǐ lǐ hēng zhe qīng​kuài de diào​zi.

   She was in a good mood, humming a light tune.

   Source: Dong Chinese Dictionary

2. 这首歌调子起得太高，我实在唱不上去。

   zhè shǒu gē diào​zi qǐ de tài gāo, wǒ shí​zài chàng bù shàng​qù.

   The key of this song is too high for me to reach the notes.

   Source: Dong Chinese Dictionary

3. 这首歌的调子非常优美，听一遍就能记住。

   zhè shǒu gē de diào​zi fēi​cháng yōu​měi, tīng yī biàn jiù néng jì​zhu.

   The tune of this song is very beautiful; you can remember it after hearing it once.

   Source: Dong Chinese Dictionary

4. 他说话的调子听起来有些不耐烦。

   tā shuō​huà de diào​zi tīng qi​lai yǒu​xiē bù nài​fán.

   His tone of voice sounds a bit impatient.

   Source: Dong Chinese Dictionary