海豚和其他海洋哺乳动物正受到海洋废物的危害。

Dolphins and other sea ___mammals are being harmed by waste in the oceans.

一个与世隔绝的小岛是观察鲸鱼等海洋哺乳动物的好地方。

A small, isolated island can be a great place to observe sea ___mammals like whales.

所有哺乳动物的一个定义性特征是能够产奶喂养幼崽。

The ability to produce milk to feed their young is a defining characteristic of all ___mammals.