3 sentences

1. 很难保持温度恒定。

   hěn nán bǎo​chí wēn​dù héng​dìng.

   It is difficult to maintain a constant temperature.

   Source: CCMatrix

2. 冷血动物没有恒定的体温。

   lěng​xuè​dòng​wù méi​yǒu héng​dìng de tǐ​wēn.

   Cold-blooded animals do not maintain a constant body temperature.

   Source: CCMatrix

3. 夏威夷的水温是非常恒定的。

   xià​wēi​yí de shuǐ​wēn shì fēi​cháng héng​dìng de.

   The water temperature in Hawaii is very consistent.

   Source: CCMatrix