Fast swimming marine predators have a streamline body, like this Ichthyosaur I have here.

快速游泳的海洋捕食者有流线型的身体，就像我这里的这只鱼龙。

Sharks come in many different shapes, too, although most sharks have streamlined bodies shaped like torpedoes to help them glide more easily through the water.

不同种类的鲨鱼形态各异，绝大部分鲨鱼的体型都是流线型，这种鱼雷式的形状有助于它们在水里轻松穿行。

They've evolved to have a narrow skull and a long flexible neck, which are believed to help streamline their bodies in the water and provide the reach and flexibility they need to bring their noses up for air.

他们狭窄的头骨和长而灵活的脖子，都有利于它在水中流线型运动，也可帮助它们抬起鼻子以增加其伸展范围和灵活性。