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沙丘如何在沙漠中移动，又为何有些沙丘保持静止？

Wind pushes sand grains along the ground in a process called saltation, gradually reshaping dune forms over time.
The speed and direction of prevailing winds determine whether dunes migrate, rotate, or remain anchored.
Vegetation roots stabilize sand by binding particles together, halting movement even under strong gusts.
Some dunes rest on bedrock or cemented layers that prevent erosion from beneath.
Star dunes grow upward instead of migrating because winds blow from multiple directions equally.
Satellite images reveal that certain mega-dunes shift only centimeters per year, while others travel meters annually.
Human activity like off-road driving can destroy stabilizing crusts and trigger sudden dune migration.
Geologists use grain-size analysis and sediment layers to reconstruct ancient wind patterns from fossil dunes.
Moisture content in sand also slows motion — damp grains stick together and resist wind lift.
This balance between movement and stillness shapes desert ecosystems and ancient trade routes alike.

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

Some dunes rest on bedrock or cemented layers that prevent erosion from beneath. 部分沙丘坐落于基岩或胶结层之上，底部因而免遭侵蚀。
Vegetation roots stabilize sand by binding particles together, halting movement even under strong gusts. 植物根系通过黏结沙粒来稳固流沙，即便强风也难以使其移动。
Star dunes grow upward instead of migrating because winds blow from multiple directions equally. 星形沙丘因多向风力均衡吹袭而向上生长，而非横向迁移。

这篇中文题目最接近哪一句？沙丘如何在沙漠中移动，又为何有些沙丘保持静止？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？风通过跃移作用推动沙粒沿地面运动，随时间推移逐渐改变沙丘形态。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） How Sand Dunes Move Across Deserts — And Why Some Stay Still How to cook noodles A maths worksheet

Some dunes rest on bedrock or cemented layers that prevent erosion from beneath.

Some dunes rest on bedrock or cemented layers that prevent erosion from beneath.

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：Some dunes rest on bedrock or cemented layers that prevent erosion from beneath.