Explanatory composition

In our daily study, work and life, everyone has written a composition, which is a narrative method to express a theme through words. How to write a composition to avoid stepping on thunder? The following are five expositions I collected, hoping to help you.

The explanatory text 1 mentions flies, which should be familiar to everyone. Yes, it is one of the five recognized pests.

The eating habits of flies are very complicated and belong to omnivorous flies. To put it bluntly, they eat everything. Most flies are small to medium size, like a mung bean. The antenna is short, with only three nodes.

There are whips at the end of the distal segment or feathery bristles on the back of the distal segment, and the mouthparts are licking and sucking. Forewing membranous, especially Yu Feixiang. The tail wing degenerates into a balance bar and is hidden under the flap at the bottom of the front wing.

Although the life span of flies is only about one month, it contains amazing reproductive ability. According to statistics, the number of eggs laid by each batch of houseflies in the laboratory is about 100, and a female fly can produce 10 to 20 batches of eggs in her life, totaling 600- 1000. In nature, each female fly can lay 4-6 batches in her lifetime, with an interval of 3-4 days, and the amount of eggs laid in her lifetime is 400-600.

According to the most conservative estimate, each female fly can produce 200 offspring, so 100 female flies only need 10 generation, and the total number of flies will reach 2 trillion! What a terrible number.

As one of the five insects, its reproductive ability is so strong that its harm cannot be underestimated. A large number of experiments have proved that a large amount of fur on the surface of flies, as well as their digestive system and blood system, can carry pathogens and then spread them to humans through contact with food. In the process of eating, flies will excrete quickly, and the excrement of the hindgut will also spread pathogens into food. For example, fly droppings have important diseases on livestock and poultry breeding, which greatly affect the production performance of livestock and poultry and threaten human health. Although flies are really annoying, they are real "flying masters".

The main flight structures of flies are: external bone collaterals and flight muscles. When flying, we flap our wings with the figure of eight. This way of flapping wings can make the air around the wings form a vortex airflow, help flies fly easily, and convert the air into the power of flies.

But it is not enough to have superb flying ability, but also to have a sensitive response, just to contract all the flies. Compound eye is a sensory organ located in the head of a fly, which can sense the surrounding situation 360 degrees, and its body hair can also sense the change of air mobility. After perceiving the threat 100 milliseconds, the fly's brain has been able to respond, calculate the best escape angle and route, and become a tool for flies to escape.

Watermelon is a very delicious fruit. There are many kinds of watermelons: beauty melons, space watermelons ... Especially in summer, people will feel particularly cool after eating frozen watermelons, which will quench their thirst and make people never tire of eating them. Men, women and children like it.

The appearance of watermelon ranges from dark green to light yellow, and then to pure white like a birdcage. Smell it. It smells like melons and vines. It's very convenient for you to tell the good from the bad with a tap. You cut it with a knife, and a fragrant smell comes to your nose. If it is a ripe melon, you will see blood-red flesh. Watermelon of that color will be very sweet. If it is pink like a watermelon bed, it will have a sour and sweet taste.

The big watermelon is as big as a basketball, and the small one is really as big as a fist. In summer, I think watermelon must be the king of fruit.

This is the delicious watermelon.

My hometown, Pan 'an, is "nine mountains, half water and half fields". She lay quietly on the land of Jiangsu and Zhejiang, like a cradle, bearing Qian Qian's thousands of children and grandchildren.

The mountains in my hometown are not majestic, but short and slow hills, like continuous humps. A series of hills are connected together, just like building a beautiful green barrier between hometown and other areas. Entering the mountains, there are beautiful birds singing, the tinkling of mountain springs and the dripping of dew everywhere. Walking up the mountain road, there are terraces of different sizes on both sides, and all kinds of herbs or crops are planted in the fields. There may be farmers working in the fields or leading cattle to plow the fields. In some seasons, there will be all kinds of wild fruits on the mountain. Pick a green bristlegrass, string wild fruits of different sizes into a string, and enjoy them while eating. You are shuttling between Shan Ye, and maybe a farmer will meet you head-on.

People in my hometown are very hospitable. When the guests come, they will take out their most abundant dishes to entertain. Some people will also take out their own white wine and yellow wine and invite you to taste it together. During the dinner, you are constantly advised to drink and eat vegetables for fear of poor hospitality. When you leave, people in the countryside will also prepare some special products for you to take back. Although it is not expensive, it is very kind and difficult to refuse.

At whose house do the old people in the village get together to chat? Although they are old and their legs and feet are a little inconvenient, if you want to know anything, you must ask them. They take everything in the village to heart, and there is nothing they don't know. When someone has a happy event, they enthusiastically go to that house to help, even if they are not relatives, as long as they are "family" and "neighbors", they will help. Children in the village are seldom at home. As soon as they finished their homework, they flew out of the house to get together with other friends to play. At night, mothers stood at the door and shouted, "It's time to go home for dinner!" " "The children went home again. Most middle-aged people in the village are busy with Chinese herbal medicine business, planting Chinese herbal medicine or other livelihoods.

This is my hometown-Pan 'an, with beautiful scenery, fresh air and simple people.

Beautiful mountains and waters are more beautiful, and mountains and rivers are peaceful. Welcome to visit!

If possible, I want to dance at the end of time. -inscription

No one knows what will happen in the world in the next second. What is predictable is called planning, not life. My time is like a boat, carrying me from morning till evening, from today to tomorrow, but I never know which direction the erratic wind will take me in the next second. Perhaps, this is the future, or suddenly see a peach garden that suddenly opens, or a thorny but still beautiful and quiet mountain road, or an inescapable desert beach. At that time, only my time will accompany me. It's up to me to hold on or give up.

Looking at the success and harvest of others, there will always be a moment of unwillingness and injustice. Why him and not me? It was just a moment, and then it calmed down. God is always fair. He gave us the same time, but you didn't choose to do what you envied. You can't blame anyone. Envy returns to envy, and your happy life is always special. When you are immersed in the success of others, your time is slipping away. I don't know whether it was success or others' success, but I still got nothing. The opportunity to enjoy one more day, one more minute, or even one second of happiness is wasted, and there is no trace with the sigh.

There is no longer a murderous desire, and I look down on Yun Qi's cloud. This state is a kind of inner return. Seeing that time is going far step by step, I finally understand that after grasping in vain, I need more courage to face it. Accept the vicissitudes of life given by time. Whether it is good or bad, it is the grace of the years. In a hundred years, we can calmly and calmly examine our inner needs and create enrichment that belongs to different stages of life.

Step by step, when people are like mountains, they no longer care about prosperity and sparseness, and they no longer worry about withering and blooming. The peace they get is like the smile of Buddha's heart. It turns out that I can be so comfortable when I let go This is indeed a desirable situation. It is slowly forged in the container of time, and some rough and vain desires are washed clean, such as porcelain, which is tempered in the flame, then cooled and shaped, and finally bid farewell to the soil, completing the internal and external meditation with another face, and being endowed with elegant connotation by time.

The elegant connotation of life is like porcelain. The smoothness and delicacy at the beginning were gradually replaced by roughness and sharpness, and the imprint left by time condensed in the gully. Even if the porcelain is finally broken and turned back into dirt, it proves that we have been to this world.

If I can, I would like to dance at the end of time to celebrate all the glory in my life.

My room, though not created by a national designer, has a unique scene. There is my paradise and my treasure house. There, I can get rid of any troubles.

When you open my door, the first thing you see is a bed covered with a fluffy blue blanket; In the middle of the bed, there is a furry and chubby bear, which belongs to my brother. It has big eyes and looks like a shining jewel at night. On the left and right sides of the bed, there are two cabinets. The cabinets are two squares, and the cabinets are twins. That makes no difference. The first square is white, and the second square is white.

On the left side of the left cabinet is my wardrobe, which is composed of four colors: white, pink, yellow and silver gray. The wardrobe is divided into three parts. There are two floors on the left, and my sheets are on the top floor. Thin and thick, both; The bottom floor is my clothes, divided by season. The innermost is winter clothes, and the outer is summer clothes. A large compartment in the middle is also divided into two floors, with spare pillows, quilts and so on. There are three drawers on the ground floor. The first drawer is my personal belongings. Money, diaries, etc ... can't be opened without my key. The second cupboard is my little brother's things, gloves and hats, all in it, and the third cupboard is towels, which are spare supplies for guests. The last big grid layer is divided into two layers, above which is my brother's winter clothes, and below which is my brother's autumn and winter summer clothes.

There is a bay window on the right side of the bed, and there are some dolls on the windowsill, which are toys for my little brother and me. There are bears, pigs, rabbits and monkeys. My little brother regards them as treasures. Only he and I can play with them. He can cry for a long time when others play without his permission.

On the left of the windowsill is my desk. The desk is white and can be compared with the white clouds in the sky. I do my homework there every day Under the desk, there is a compartment full of my school supplies. Under this grid, there is a small cabinet twice as big as this one, in which my skates are placed.

Above the desk is my bookshelf. The bookshelf has seven small squares. There is one extra-curricular book I have read, such as The Little Prince, Gulliver's Travels, How Steel was Tempered, The Water Margin, The Journey to the West and so on. The waste book I used has a grid. At the same time, next to it is a grid filled with my old exercise books. There is also a grid for primary school books, some of my previous books are in it, and there is also a grid for all junior high school Chinese books, globes, lotus flowers and so on. They are very neat, just like soldiers after military training. On it, there are two big red flowers for Children's Day, which are very beautiful. All the other squares are empty.

This is my room, very chic, although not particularly large, but warm and harmonious.