You will listen to part of a lecture and answer a question about it. After you hear the question, you will have 20 seconds to pr

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问题 You will listen to part of a lecture and answer a question about it. After you hear the question, you will have 20 seconds to prepare a response and 60 seconds to record the response.
Now listen to part of a lecture in a biology class.
Using points and examples from the lecture, describe the two benefits of weeds and their function.
Now listen to part of a lecture in a biology class.
    Weed control is one of the most important crop protection activities undertaken in farming systems. Most people mistakenly consider weeds to be entirely detrimental and troublesome because they generally reduce crop yield by competing for resources such as water, light, soil nutrients and space. However, in some scenarios using weeds to assist crop yield had been proven tremendously beneficial for a number of reasons. Let’s take a look at two examples to see how the use of weeds in tandem with coffee plants has helped farmers maintain healthy crops.
    First, weeds help lower wind and water erosion and offer other forms of environmental protection. The coffee plant is often planted on steep mountain slopes which are prone to high speed winds and heavy rains. The root systems of the weeds help hold in place valuable and nutrient rich soil for the coffee plant to use. Because the roots are strong, the soil is not easily carried away by heavy winds. The same is true for heavy rains. The roots hold the soil together so that the nutritious soil isn’t washed away.
    Another notable benefit of weeds for the coffee plant is protection from destructive pests and insects. There’re several types of insects that eat the leaves of the coffee plant. However, these same insects prefer to eat the leaves of weeds more. This led some rather ingenious farmers to plant weeds amongst their coffee plants to provide an alternative food source for these insects. So rather than use harmful and expensive insecticides, farmers came up with a natural and cheap alternative to pest control. And as you can see, weeds, traditionally thought to only have a negative impact on agriculture, have in fact many positive attributes. Soil stabilization and pest control are only two of many benefits of weed use in agriculture.

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答案 Contrary to traditional perception, weeds actually play an important role in increasing the crop yield. For example, weeds planted together with coffee plants are beneficial to the crop health by stabilizing the rich soil and attracting the pests. For one thing, the root systems of the weeds can hold in place the nutrient soil, protecting it from the high-speed winds and heavy rains in the mountainous area. For another, weeds serve as a cheap and natural alternative to pesticides by attracting pests and insects that feed on leaves of coffee plants. As the leaves of weeds are more appealing to those pests, they’ll choose weeds over coffee plants and therefore the latter can grow healthier. To sum up, soil stabilization and pest control are two prominent benefits of weed use in coffee planting.

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