2 sentences for 膨胀 (péng​zhàng)

1. 气体受热后体积会膨胀。

   qì​tǐ shòu​rè hòu tǐ​jī huì péng​zhàng.

   Gas expands when heated.

   Source: Dong Chinese Dictionary

2. 他在取得一点成绩后，自我意识就开始膨胀。

   tā zài qǔ​dé yī​diǎn chéng​jì hòu, zì​wǒ yì​shí jiù kāi​shǐ péng​zhàng.

   After achieving a little success, his ego began to swell.

   Source: Dong Chinese Dictionary