3 sentences

1. 我在当当网上买了几本书。

   wǒ zài Dāng​dāng wǎng​shàng mǎi le jǐ běn shū.

   I bought a few books on Dangdang.com.

   Source: Dong Chinese Dictionary

2. 那口大钟发出了当当的响声。

   nà kǒu dà zhōng fā​chū le dāng​dāng de xiǎng​shēng.

   The large bell made a 'ding-dong' sound.

   Source: Dong Chinese Dictionary

3. 由于急需用钱，他只好把家里的旧电脑拿去当当了。

   yóu​yú jí xū yòng qián, tā zhǐ​hǎo bǎ jiā​lǐ de jiù diàn​nǎo ná​qù dàng​dàng le.

   In urgent need of money, he had no choice but to pawn the old computer from his home.

   Source: Dong Chinese Dictionary