新托福听写训练 第7期

Higher animals like dogs, horses, even human being look like their parents when they are born. There are some minor¹ changes that occur as these animals grow. But the basic form and structure stay the same. Now this is called direct development, which is quite different from metamorphosis. When lower animals like ants, flies, or sea urchin² emerge from the eggs, they don't look at all like their parents. Only after series of major changes do they carry on the characteristics of their parents. Butterfly and moth³ provide the best example of what biologists call complete metamorphosis because they pass through four distinct stages of extreme changes. Here is the illustration of butterfly at each of the four stages of complete metamorphosis.The first stage is the egg. Butterflies usually lay their eggs on plants and these plants provide food when they transform into larvae⁴, the second stage. After about months in this stage, a butterfly larvae spins the cocoon⁵ of silk around itself. A larvae in the cocoon is also called pupa. So it is known as the pupil stage. The pupil stage is the period of inactivity when larvae structures evolved adult structures. Depending on the species, the pupil stage can last anywhere a few days to several months. When the pupa finally mature into the adult butterfly. It pushes its way out of its cocoon and cross onto a twig⁶ or tree land and pumps blood into the trunk and wing until they are full size and strong.Now some insects like grasshoppers⁷ and roaches have only 3 stages, egg, larva, and adult. When an animal skips the pupil stage, it is called incomplete metamorphosis. It's not only insects that undergo metamorphosis. Frogs and toads⁸ are the most< animals >well know example of other form changing animal. Frogs lay their eggs in water and the eggs hatch into tadpole⁹. A tadpole looks more like little fish, because it has tails and no legs. But it gradually loses its tail and develops into four-legged frog.

1 minor   

adj.较小(少)的，较次要的；n.辅修学科；vi.辅修

参考例句：

• The young actor was given a minor part in the new play.年轻的男演员在这出新戏里被分派担任一个小角色。
• I gave him a minor share of my wealth.我把小部分财产给了他。

2 urchin   

n.顽童；海胆

参考例句：

• You should sheer off the urchin.你应该躲避这顽童。
• He is a most wicked urchin.他是个非常调皮的顽童。

3 moth   

n.蛾，蛀虫

参考例句：

• A moth was fluttering round the lamp.有一只蛾子扑打着翅膀绕着灯飞。
• The sweater is moth-eaten.毛衣让蛀虫咬坏了。

4 larvae   

n.幼虫

参考例句：

• Larvae are parasitic on sheep.幼虫寄生在绵羊的身上。
• The larvae prey upon small aphids.这种幼虫以小蚜虫为食。

5 cocoon   

n.茧

参考例句：

• A cocoon is a kind of silk covering made by an insect.蚕茧是由昆虫制造的一种由丝组成的外包层。
• The beautiful butterfly emerged from the cocoon.美丽的蝴蝶自茧中出现。

6 twig   

n.小树枝，嫩枝；v.理解

参考例句：

• He heard the sharp crack of a twig.他听到树枝清脆的断裂声。
• The sharp sound of a twig snapping scared the badger away.细枝突然折断的刺耳声把獾惊跑了。

7 grasshoppers   

n.蚱蜢( grasshopper的名词复数 )；蝗虫；蚂蚱；（孩子）矮小的

参考例句：

• Grasshoppers die in fall. 蚱蜢在秋天死去。 来自《简明英汉词典》
• There are usually a lot of grasshoppers in the rice fields. 稻田里通常有许多蚱蜢。 来自辞典例句

8 toads   

n.蟾蜍，癞蛤蟆( toad的名词复数 )

参考例句：

• All toads blink when they swallow. 所有的癞蛤蟆吞食东西时都会眨眼皮。 来自《简明英汉词典》
• Toads have shorter legs and are generally more clumsy than frogs. 蟾蜍比青蛙脚短，一般说来没有青蛙灵活。 来自辞典例句

9 tadpole   

n.[动]蝌蚪

参考例句：

• As a tadpole changes into a frog,its tail is gradually absorbed.蝌蚪变成蛙，它的尾巴就逐渐被吸收掉。
• It was a tadpole.Now it is a frog.它过去是蝌蚪，现在是一只青蛙。