2 sentences

1. 音乐厅里，热烈的掌声此起彼伏。

   yīn​yuè​tīng lǐ, rè​liè de zhǎng​shēng cǐ​qǐ​bǐ​fú.

   In the concert hall, rounds of warm applause rose and fell.

   Source: Dong Chinese Dictionary

2. 那段时期，各地的罢工运动此起彼伏。

   nà duàn shí​qī, gè​dì de bà​gōng yùn​dòng cǐ​qǐ​bǐ​fú.

   During that period, strikes broke out one after another in various places.

   Source: Dong Chinese Dictionary