4 sentences

1. 春天的天气总是如此多变。

   chūn​tiān de tiān​qì zǒng​shì rú​cǐ duō​biàn.

   Spring weather is always so changeable.

   Source: Dong Chinese Dictionary

2. 公司必须适应多变的外部环境。

   gōng​sī bì​xū shì​yìng duō​biàn de wài​bù huán​jìng.

   The company must adapt to the changing external environment.

   Source: Dong Chinese Dictionary

3. 在这个多变的时代，很少有永恒不易的法则。

   zài zhè​ge duō​biàn de shí​dài, hěn shǎo yǒu yǒng​héng bù​yì de fǎ​zé.

   In this ever-changing era, few rules remain forever unchanged.

   Source: Dong Chinese Dictionary

4. 他在研究一个复杂的多变函数。

   tā zài yán​jiū yī gè fù​zá de duō​biàn hán​shù.

   He is studying a complex multivariable function.

   Source: Dong Chinese Dictionary