2 sentences

1. 每天有成百上千的游客参观这个博物馆。

   měi tiān yǒu chéng​bǎi​shàng​qiān de yóu​kè cān​guān zhè gè bó​wù​guǎn.

   Hundreds upon hundreds of tourists visit this museum every day.

   Source: Dong Chinese Dictionary

2. 这种鸟喜欢合群，经常成百上千地飞往南方。

   zhè zhǒng niǎo xǐ​huan hé​qún, jīng​cháng chéng​bǎi​shàng​qiān de fēi​wǎng nán​fāng.

   These birds are gregarious and often fly south in the hundreds or thousands.

   Source: Dong Chinese Dictionary