4 sentences

1. 他凝视着那张照片许久。

   tā níng​shì zhe nà zhāng zhào​piàn xǔ​jiǔ.

   He gazed at that photo for a long time.

   Source: Dong Chinese Dictionary

2. 他沉默了许久，这才突然省过味儿来。

   tā chén​mò le xǔ​jiǔ, zhè cái tū​rán xǐng​guò wèi​r lái.

   He was silent for a long time before he suddenly realized what was going on.

   Source: Dong Chinese Dictionary

3. 他等了许久，过了好些时候才见到她。

   tā děng le xǔ​jiǔ, guò le hǎo xiē shí​hou cái jiàn​dào tā.

   He waited a long time, and it was quite a while before he saw her.

   Source: Dong Chinese Dictionary

4. 他在梦境中见到了许久未见的老朋友。

   tā zài mèng​jìng zhōng jiàn​dào le xǔ​jiǔ wèi jiàn de lǎo péng​you.

   In his dream, he saw an old friend he hadn't seen for a long time.

   Source: Dong Chinese Dictionary