2 sentences

1. 看到那感人的一幕，我不由得流下了眼泪。

   kàn​dào nà gǎn​rén de yī mù, wǒ bù​yóu​de liú​xià le yǎn​lèi.

   Seeing that touching scene, I couldn't help but shed tears.

   Source: Dong Chinese Dictionary

2. 他听后不由得发了一会儿愕，半天说不出话来。

   tā tīng hòu bù​yóu​de fā le yī​huì​r è, bàn​tiān shuō bù chū huà lái.

   He was stunned for a moment after hearing it and was speechless for a long time.

   Source: Dong Chinese Dictionary