3 sentences

1. 古人云：三人行，必有我师焉。

   gǔ​rén yún: sān rén xíng, bì yǒu wǒ shī yān.

   The ancients said: 'In a group of three, there is always someone I can learn from.'

   Source: Dong Chinese Dictionary

2. 如果不亲身实践，焉能取得成功？

   rú​guǒ bù qīn​shēn shí​jiàn, yān néng qǔ​dé chéng​gōng?

   How can one achieve success without personal practice?

   Source: Dong Chinese Dictionary

3. 这种罕见的药材产于焉地，目前还不得而知。

   zhè zhǒng hǎn​jiàn de yào​cái chǎn yú yān dì, mù​qián hái bù​dé'ér​zhī.

   The origin of this rare medicinal herb is currently unknown.

   Source: Dong Chinese Dictionary