作业帮 > 英语 > 作业

nature science或者social science 的趣闻

来源:学生作业帮 编辑:神马作文网作业帮 分类:英语作业 时间:2024/11/20 19:10:15
nature science或者social science 的趣闻
要英文的 比较有意思的 口述差不多2 3分钟的小段落
nature science或者social science 的趣闻
When you go into a forest,it is dark under the trees.The trees leaves have collected most of the light on its way down from the sky.Green leaves are a plant’s own food factory.They produce the food that the plant needs for growing,and for making flowers,fruits and seeds—and new leaves.Light energy from the sun is used by the leaves to turn carbon dioxide and water into oxygen and sugar.This process is called photosynthesis.All green plants use sugar as a basic food for growing.
Leaves come in an amazing variety of shapes and sizes:cotoneaster has a simple oval leaf,pointed at the tip; nettles have saw-tooth edges and are covered with stinging hairs; blackberry leaves are compound with usually three or sometimes five leaflets.Each kind of plant has its own special shape of leaf,and you can tell which plant a leaf belongs to just from its shape.Leaves can be divided into two types – simple leaves and compound leaves.
Leaves cover a tree rather like clothes.Over a million leaves are needed to clothe a big tree.Without them,the tree is a bare skeleton.
Leaves need a lot of water.The water flows up through the stem of the plant as sap and into the veins of its leaves.Cacti live in very dry desert country in north and south America.Their fat stems are used to store water and their green skins photosynthesizes,just like leaves.Their leaves are sharp dry spines which give off no water and protect the plant from being eaten by animals.
Leaves have a lot to do with rain.We can say that ‘No Leaves,No Rain’ .Where people cut down forest trees and destroy the natural plant cover,the land often turns to desert because the air becomes dry.
Most leaves are green,and this is because they have chlorophyll in their cells.Chlorophyll is a green pigment that absorbs energy from the sun.Chlorophyll is important for photosynthesis.But not all leaves are green,and photosynthesis is not the only thing that leaves can do.Some special leaves like Venus Flytrap leaves can catch insects and digest them as plant food.
Some special leaves can catch insects while in most cases it is animals that depend on leaves for food.We call them herbivores,which means most animals are plant-eaters.We people eat a lot of plants(vegetables more exactly ) too.
When leaves get old,they change colour,usually from green to yellow,and then,they shed and achieve their lives.
I have made a leaf collection when I was a child.Collecting leaves of as many as I can find in school or on my way home is a great pleasure.I would spend a whole afternoon electing the leaves carefully according to its shapes and size.Sometimes I would make them beautiful bookmarks.Though what I did was just for fun,we know that most great botanists have done the same thing in their childhood.
Now the world is becoming more and more industrial while we pay less and less attention to the nature.I think it would be pity if one day we could only explore the nature in books.