科学素养与生活应用·英语30篇（5）

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秋叶变色源于色素分解与新合成

As daylight shortens, trees stop producing chlorophyll, revealing yellow carotenoids already present.
Red anthocyanins are newly synthesized in fall when sugars get trapped in leaves.
Cool nights and sunny days increase sugar accumulation, boosting red pigment production.
Soil moisture and nutrient levels influence intensity and timing of color changes.
Deciduous trees shed leaves to conserve water during winter dormancy periods.
Leaf abscission layers form at petioles, cutting off transport and sealing the cut surface.
Different species show distinct colors due to genetic control over pigment expression.
Maple trees often turn bright red, while oaks tend toward russet and brown hues.
Frost delays color development but accelerates leaf drop once it arrives.
This seasonal transformation illustrates how plant physiology responds precisely to environmental cues.

听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。

Deciduous trees shed leaves to conserve water during winter dormancy periods. 落叶树通过脱落叶片，在冬季休眠期节约水分。
Frost delays color development but accelerates leaf drop once it arrives. 霜冻会延缓变色进程，但一旦来临便加速落叶。
As daylight shortens, trees stop producing chlorophyll, revealing yellow carotenoids already present. 随着日照变短，树木停止合成叶绿素，原本就存在的黄色类胡萝卜素因而显现。

这篇中文题目最接近哪一句？秋叶变色源于色素分解与新合成一次学校运动会的通知一份超市购物清单

课文第一句的意思更接近？随着日照变短，树木停止合成叶绿素，原本就存在的黄色类胡萝卜素因而显现。今天学校放假了。请把窗户打开。

这一课主要在讲什么？（看英文标题） Why Autumn Leaves Change Color Due to Pigment Breakdown and Synthesis How to cook noodles A maths worksheet

Deciduous trees shed leaves to conserve water during winter dormancy periods.

Deciduous trees shed leaves to conserve water during winter dormancy periods.

第一版：录下来、回听、再听标准音。系统打分以后再加。

用今天的表达，自己说一句。

例子：Deciduous trees shed leaves to conserve water during winter dormancy periods.