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With the rapid development of information technology, computers have penetrated into all aspects of our lives and play a huge role. Compared with other disciplines, computer science has great particularities, which not only has strong practicality, but also has fast updating of knowledge points.
1. According to the actual situation of the school and students, make reasonable trade-offs for the teaching content.
The existing computer textbooks seldom take into account the differences in regions, students' knowledge, and school experimental equipment, so teachers must first combine the actual situation of schools and students, make reasonable trade-offs on the knowledge points of the textbooks, select the essence and key points, and avoid being exhaustive. This is significantly different from other disciplines such as mathematics, physics and chemistry. Other disciplines such as mathematics, physics and chemistry emphasize the comprehensiveness of knowledge points and the interconnection between knowledge points, while the computer, as a tool, focuses on the application of a certain aspect, and the knowledge points involved in various applications are more independent of each other and less connected.
This ** is quoted from the magazine "" The magazine is a computer journal level senior academic journal published at home and abroad by the Ministry of Industry and Information Technology of the People's Republic of China and sponsored by the North China Institute of Computing Technology, the journal of the China Computer Federation, which has been changed from a bimonthly journal to a monthly journal since 2010, with a large 16 openings. Submissions are welcome (both Chinese and English). Coverage:
Insist on publishing innovative, cutting-edge, oriented, pioneering and exploratory scientific research achievements in various disciplines of computer (hardware and software).
Therefore, there is a relatively large space for us to select the knowledge points of computer science. We can consider the practicability of the knowledge points and the degree to which students can accept them, as well as the school's experimental equipment and social needs, and other factors, and should avoid copying the teaching materials in their entirety, otherwise students will not be able to grasp the knowledge points well because of too many knowledge points, too difficult, and the experimental equipment is not supported, or they can not be used if they have mastered it.
2. "Task-based teaching" runs through the whole classroom.
At present, the task-driven teaching model is often referred to as the teacher's design of the teaching content into one or more specific tasks, so that students can master the teaching content and achieve the teaching goal by completing specific tasks. The advantage of "task-based teaching" is that as soon as the "task" is proposed, it can make students have a strong desire for knowledge; Students have typical examples to refer to when learning knowledge points, which is profound and easy to understand. When completing the "task", it can deepen the understanding of the knowledge points, which is conducive to cultivating practical ability.
For example, in the teaching of programming, when teaching the chapter on window communication protocol, I first assigned students a "task": to design an online chat system. As soon as the "task" was proposed, the students' interest was very high.
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1. According to the size of the plant If it is a small seedling, it is generally watered by "a small amount but high frequency". You can pour it once a day, but not too much. However, for plants that have already reached adulthood, the method of "more water at a time and longer intervals" is generally adopted.
It can be done once a week or so, but the amount of watering at one time is more...
2. According to the state of the soil This is also a good way to judge whether watering is needed. Depending on the factors, the time it takes for the soil to dry out will also vary. If it is observed that the soil is dry, then it is time for the next watering.
3. According to the change of seasons Different seasons, the frequency of watering is naturally different. Spring and autumn are about the same frequency, almost once a week. If the ventilation is good, it can be once every three or four days.
In summer, the plant will be dormant when the temperature is high, and the frequency should not be too high, generally once every half a month to 20 days. In winter, it is also dormant when it is cold, and the frequency is the same as in summer.
4. According to the soil and container If the soil contains many particles, then the permeability will be relatively good, so the watering interval should be shortened. The impact of containers is also significant. If you use a terracotta potted plant, it is susceptible to water shortage.
Size also plays a role, with large diameters evaporating quickly and therefore short watering intervals.
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1. The frequency of watering is the number of watering, spring and autumn are the seasons for plant growth, all the normal watering can be done, you can see the dryness and wetness of the soil; If the weather is good, the water can be watered once every 3 to 4 days, usually once a week.
2. In summer and winter, the succulent will enter a dormant state, and the watering interval can be widened at this time; In winter, it can be watered once every 15 to 20 days; In summer, the water evaporates quickly, so you can water it once a week, and the amount should not be too much.
3. If it is a seedling that has just been planted or bought, it should be watered once a day, but the amount of watering should not be too much; Adult succulents are about once a week, and old succulents are about twice a month.
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How often should succulents be fertilized, how to fertilize, what fertilizer to use, and how often to water them, I will summarize the precautions for raising succulents for your reference only.
Succulents are fertilized once every two or three months is enough, and generally diluted with potassium dihydrogen phosphate and sprinkled to irrigate the roots. The native land of succulents is mostly in the desert wilderness, the soil is poor, and there are few nutrients, so there are many planting enthusiasts who advocate that the planting of succulents should simulate the original plum disturbance environment, no fertilization, less fertilization. But plant growth, fertilizer is necessary, 100,000 why tells us, plant growth three elements, was discovered by the British, through the ashes obtained after burning plants, scientists analyzed a large amount of nitrogen, phosphorus, potassium, and trace amounts of other elements.
So it was concluded that the three elements of plant growth are: nitrogen, phosphorus, and potassium.
The succulents are thoroughly dried before watering. It is watered once every 5 days in summer and once every 20 days in winter. It should be poured thoroughly each time, which is the outdoor pouring method, and if it is indoors, it should be extended for 3-5 days.
Spring, summer and autumn are best watered in the evening or in the cool afternoon, while in winter, because the temperature is too low, it is best to choose to water at noon. When watering, water along the edge of the pot and do not allow water to slip onto the leaves. Try to avoid water flowing into the center of the leaf to form stagnant water, which will act like a magnifying glass, gathering sunlight to a point and burning the succulent leaves directly.
If you accidentally pour it into the center of the leaf, you can blow the water off or blot it dry with a paper towel.
There are many varieties of succulents, and novices can choose some plants that are hardy and very well adapted to the environment, such as the common succulents of the genus Sedum or the genus Perennial.
Choosing hardy plants does not mean that these succulents can be maintained in extreme conditions for a long time, and succulents with thick cortices, such as Haworthia succulents.
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1. Spring and autumn watering: water succulents every three days to promote their vigorous growth. 2. Summer watering:
Succulents are dormant in the summer and need to be watered off to avoid root rot. 3. Winter watering: water evaporates quickly, and it can be watered every 1-2 months.
4. Precautions: Do not sprinkle water on the center of the succulent leaf when watering.
1. Spring and autumn watering
Spring and autumn are the most suitable seasons for the growth and development of succulents, and it is also the peak period for development. The frequency is controlled once every 3 to 4 days, but it is forbidden to splash water directly on the succulent plant during the watering process, which will cause the risk of rotting and smelling succulent leaves.
2. Summer irrigation
Although summer is the season of high temperature and heat, the amount of water evaporation is relatively large, but it is also the dormant period of succulents. Succulents have a certain drought tolerance, so it is better to keep the soil dry, otherwise too much watering is too wet, which is against the law of succulent growth, which will cause succulent malaverium and shrinkage, and reduce ornamentality.
3. Winter watering
Winter is the hottest season of the year and is also the dormant period of the succulent. The difference is that at this time, the succulent development is very slow, even close to stopping growth, so the water requirement is very small. Watering 1 or 2 times a month can fully meet the growth needs, as long as the soil is not dry and white, there will be no big problem.
4. Precautions
To ensure that the water applied to succulent irrigation is clean and clean, the tap water that is usually used needs to be left to stand for 1 or 2 days in advance to volatilize the chlorine in the water body before use. Do not water succulents on cloudy days and during the rainy season. In case of water damage, stop the water immediately and move the succulent to a ventilated environment to quickly drain the silt in the potting soil.
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Succulents can be watered every other week, summer plants enter the dormant period, stop growing, should be watered every 10 days, the temperature decreases in winter, to water twice a month or postpone watering, and watering succulents can take the method of watering and spraying, irrigation along the edge of the pot in spring and autumn, and spraying water mist around in summer.
Succulents can be watered every other week in the spring and autumn seasons when the temperature is suitable, and the temperature rises in summer, but the succulents will enter the dormant period, so they should be watered every 10 days instead, and the cold tolerance of the succulents is poor, and the water should be strictly controlled when the temperature decreases in winter, and they can be watered once every half a month or postponed.
When watering the succulent, it is necessary to take the method of watering or spraying, generally in spring and autumn, you can water the water along the edge of the pot in the soil, soak the soil completely, and then put the succulent in a ventilated place, and in summer to spray water mist around the succulent to improve the humidity of the environment.
Succulents do not have high requirements for water quality, and can generally be watered with non-polluted river and lake water to supplement trace elements for plants, or accumulate rainwater in the rainy season to water succulents and adjust the acid-base ratio of the soil.
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First, the watering method.
1. For the small succulent that has just been cultivated, its root system has not grown completely, and there will be a certain amount of water in the cultivation soil, so there is no need to water too much. Usually, you just need to wet the surface of the soil, you don't need to water it thoroughly.
2. For the succulent with complete root growth, we need to water it thoroughly, and if the long-term watering stops halfway, it is also very unfavorable to its growth. When giving water, pour water into the soil, not the roots, and do not water the leaves of the plants.
3. Secondly, it is watering when it rains, and you generally don't need to water too much in the rainy season. When it rains, the air itself is very humid, and the water in the soil cannot evaporate, so you can replenish the water after the rain stops for a period of time, otherwise the water will not evaporate, and it will be easy to rot the roots.
Second, the frequency of watering.
When watering succulents, the most scientific watering method is not to fix the watering time, and you should wait for the cultivation soil to dry up and then replenish the water. In spring and autumn, the weather is very good, you can water it once every 3 days or so, and in summer and winter, it will temporarily stop growing, and it is best to water it once a week or half a month. Depending on the season, the watering time should also be changed.
In addition, it can be provided with nutrients using Bika water-soluble fertilizer**.
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There is no fixed time for how long a succulent needs to be watered after planting, and the interval should be decided according to different situations. In the first case, if the succulent root system is not damaged, but the pot is simply moved, then it can be watered every 3 days, otherwise the soil is too wet and it will rot.
In the second case, prune the succulent root system and replant it, or if you plant it in dry soil, you can water it immediately to keep the soil slightly moist. However, if the soil is moist at the time of planting, it should be watered at an interval of 5-7 days.
If watering is needed, be careful not to splash water on the succulent leaf rows, and stay away from the roots, as it will rot easily if it is too close. Don't water it too much, because the root system of the plant has not recovered well when it is first planted, and it will be difficult to absorb too much water.
Spring is the best season for cuttings. If you want to have a high survival rate, watering and moisturizing are the most important. These are cuttings that have been taken in the last month, and many have already sprouted.
How to water succulents in spring, whether the soil is dry or not, water.
1. Fertilization time.
Generally, fertilization is carried out during the growing and flowering periods, once a half month, and is applied together with watering until the seed pods are mature. In general, it should be done in the morning or evening on a sunny day. In addition, it is also necessary to control the flowering period and coordinate the flowering time of the individual, which can be applied less or not at all. >>>More
Cut it to dry the wound and insert it in the soil.
How do you pot the succulent cuttings?