听写材料23.海星

正确原文：

Welcometo our aquarium. As we begin our tour, the first animal we will see today isthe starfish. You probably have seen pictures of the starfish, but in a fewminutes you will see some live ones and learn a little about their structureand life cycle. First of all, starfish are not really fish, they belong to the familyof echinoderms which are spiny, skinned sea animal. That is, their skin iscovered with thorny bumps. Most starfish have five arm-like extensions on theirbodies. And so they look like a five-pointed star. But some other kinds have asmany as 40 or more arms. Starfish, like other members of the echinoderm family,have what’s called radial symmetry. All that means is that the body parts of theseanimals are arranged around the center, kind of like spokes of a wheel around ahub. One of the special features of the starfish is that it can drop off armsas a defensive reaction, to get away from an attacker, for example. They canthen grow new arms to replace the old ones. Starfish reproduce by releasingeggs into the sea. These eggs develop into larvae, and can swim freely. Thereearly forms which are what larvae are, differ from adult starfish, because thelarvae have bilateral symmetry. That means that the two halves of the larvaelook exactly the same, which makes them look a lot different from the laterform of the starfish. Eventually the larvae sink to the ocean bottom and changeinto the adult radial form. If you don’t have questions, we will go in now andsee some of the creatures in person.

生词摘录：

1.    aquarium: n. 水族馆

2.    starfish: n. 海星

3.    echinoderm: n. 棘皮类动物

4.    spiny: adj. 多刺的

5.    skinned: adj. 有皮的

6.    thorny: adj. 多刺的

7.    bump: n. 肿块

8.    extension: n. 伸长，延伸

9.    a five-pointed star: 五角星

10. radial symmetry: 径向对称

11. spoke: n. 辐条，轮辐

12. hub: n. 轮轴

13. larvae: n. 幼虫

14. bilateral symmetry: 两侧对称：沿一条中轴身体被一平面分为左右同等的两部分的对称排列，如有机体或身体部分

15. creature: n. 动物