Mammals哺乳动物

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Mammals

Most mammals look much like their parents when they are born. They have nearly the same shape but are not the same size. As mammals live and grow, they change in size. Other body parts will also be changing as they become older. When they are adults, they can become parents of babies who look much like themselves.

Some mammals like the opossum and the kangaroo give birth to their young when the babies are too small to live entirely away from the mother's body. These babies must live in a special pouch that the mother has. They will stay until they are strong enough to be out on their own.

Many baby mammals are quite helpless. They must be cared for by their mothers or someone else. The female mammal is able to make milk for her young. If your dog or cat has had babies, you have been able to observe the mother feeding her young.

Whales are mammals. If you know that whales are mammals, then you also know some other things about baby whales. You know that they are born alive and that they must live on the milk of the mother. You know, too, that whales are lungbreathers and are not gill-breathers as fish.

Whales are among the first animals that you are told about in Genesis. Even though whales are the last animals you will study about in this life space, you must remember how important they are.

必背词汇

练 习

Study these science words.

1. Underline the word in each line that has the right spelling.

(1) mammal mamle mamal mammel mamml

(2) adolt adilt adult addult adullt

(3) puple puppa pupal pupa popa

(4) larva lurva larrva lorva larve

2. Underline the word in each line that does not belong.

(1) egg larva pupa mammal adult

(2) egg tadpole adult frog insect

(3) three body parts two antennae amphibian

(4) six legs butterfly spider cricket moth fly

译 文

哺乳动物

大多数哺乳动物刚出生时长得与自己的父母很像，外形几乎一样，只是大小不同。随着这些动物长大，它们的体型会发生变化。身体的其他部分也会随着年龄增长而发生变化。成熟之后，它们就会产下和自己外形相似的宝宝。

一些哺乳动物如负鼠、袋鼠，会在幼崽还不能够完全脱离母体时，就将其生产下来。这些孩子必须在母体拥有的一个特殊的育儿袋里成长。它们会一直待在里面，直到自己足够强壮，能独自出来生存为止。

许多哺乳动物的幼崽非常脆弱，它们必须依靠母亲或其他动物的照顾才能存活。雌性哺乳动物能够分泌乳汁来喂养小幼崽。如果你家的狗或猫生产过，你就应该观察过它们是如何喂养幼崽的。

鲸鱼属于哺乳动物类，如果你知道这一点，那么应该也知道关于鲸鱼宝宝的其他相关知识。它们是分娩出生的，必须吃母乳才会长大。此外，鲸鱼是用肺呼吸，而不像鱼是用鳃呼吸。

《创世纪》中鲸鱼是最早被提到的动物，尽管鲸鱼是地球上最后被研究的动物，但你必须牢记它们是非常重要的。

练 习

学习这些科学词汇。

1. 在每一行中拼写正确的单词下面划横线。

2. 在每一行中不属于同类的单词下面划横线。

(1) 卵 幼虫 蛹 哺乳类动物 成虫

(2) 卵 蝌蚪 成虫 青蛙 昆虫

(3) 三个身体部分 两根天线 两栖动物

(4) 六条腿 蝴蝶 蜘蛛 蟋蟀 蛾 苍蝇

答 案

1.(1) mammal (2) adult (3) pupa (4) larva

2.(1) mammal (2) insect (3) amphibian (4) six legs