空气的净化处理怎么样的?

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问题:

空气的净化处理怎么样的?

考点:暖通空调暖通空调题库
题型:问答题 简答题

Mulch is a protective cover of material that is spread on top of soil.It is usually made out of organic material, like crop waste.Farmers may keep the remains of maize or other crops on top of the soil.This creates mulch on the soil surface.The plant remains help protect the soil against wind and water damage.Mulching is one of the best things people can do for their plants.It also helps keep the soil from getting dry, and reduces the need for watering plants.It also limits temperature changes in the soil.And it stops unwanted plants, or weeds,from growing.

Organic mulch improves the condition of soil.As the mulch breaks down, it provides material which keeps the soil from getting hard.This improves the growth of roots and increases the movement of water through the soil.It also improves the ability of the soil to hold water. Organic mulch contains nutrients for plants.It also provides a good environment for earthworms and other helpful organisms in the soil.

It is easy to find organic mulch materials.Cut­up leaves and small pieces of tree bark can be used.Grass cuttings are also a good mulch for plants. Mulch from newspapers works well in controlling weeds.

The best time to add mulch depends on your goal.Mulch provides a thick barrier between the soil and the air.This helps to reduce temperature changes in the soil. As a result,mulched soil will be cooler than other soil in the summer.In winter, the mulched soil may not freeze as deeply as other soil.The best time is after the ground has frozen, but before the coldest weather arrives.Spreading mulch before the ground has frozen may attract small animals searching for a warm place to spend the winter.Delaying the spreading should prevent this problem.The animals will probably find another place to live.

小题1:The author tells us the following EXCEPT________.

A.what mulch is and its benefits

B.the best time to add mulch

C.what can be mulched on the soil surface

D.the bad effects of mulch小题2:The following can be used as organic materials to make mulch EXCEPT________.

A.tree barks

B.cut­up leaves

C.grass cuttings

D.plastic小题3:Which of the following is the benefit of mulch?

A.Protecting the soil against wind and water damage.

B.Keeping the soil wet and reducing the need for watering plants.

C.Reducing temperature changes in the soil and stopping unwanted weeds

growing.

D.All of the above.小题4:The main idea of Paragraph 2 is that organic mulch can________.

A.improve the condition of soil

B.improve the ability of the soil to hold water

C.provide a good environment for earthworms

D.improve the growth of roots and increase the movement of water through thesoil

小题5:From the last paragraph, we know ________.

A.the best time to add mulch is in spring and summer

B.the best time to add mulch is after the coldest weather arrives

C.the best time to add mulch depends on weather

D.choosing the best time to add mulch can avoid attracting small animals

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如何根据碳当量评判钢材焊接性?

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我国标准规定加速器X射线的深度剂量曲线图的检定周期()

A.每日

B.每周

C.每月

D.每半年

E.每年

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《素问·举痛论》曰:"劳则喘息(),外内(),故气耗矣。"

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从成熟到过熟.烤后烟叶的弹性逐渐()。

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