Water and other liquids can stain unprotected wood surfaces. 水和其他液体会污损未加保护的木材表面。
Although some marine mammals are protected by environmental laws, many remain unprotected. 尽管有一些海洋哺乳动物受到了环境法的保护，但还有很多不在其中。
The lack of a shell leaves the larvae unprotected against predators. 没有外壳保护使这些幼虫不能抵御天敌的捕食。