STEM与日常科技·英语30篇（5）

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细菌如何建造更坚固的混凝土

Traditional concrete cracks easily under stress, letting water and rust damage steel reinforcements.
Scientists discovered certain soil bacteria, like Bacillus pasteurii, can produce limestone naturally.
When mixed into concrete with calcium lactate and oxygen, these microbes ‘breathe’ and mineralize.
Their metabolic activity forms tiny calcium carbonate crystals inside micro-cracks.
This self-healing process seals gaps up to 0.5 mm wide within three weeks.
The repaired concrete regains up to 90% of its original strength without human intervention.
Unlike polymer additives, bacterial healing works repeatedly as new cracks appear.
Field trials show bridges and tunnels using this bio-concrete last 20–30% longer.
It also cuts long-term maintenance costs and reduces CO₂ emissions from repairs.
Here, microbiology meets civil engineering in a quietly revolutionary way.

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

Their metabolic activity forms tiny calcium carbonate crystals inside micro-cracks. 其代谢活动在微裂缝内形成微小的碳酸钙晶体。
Here, microbiology meets civil engineering in a quietly revolutionary way. 在这里，微生物学与土木工程以一种静默而革命性的方式交汇。
Unlike polymer additives, bacterial healing works repeatedly as new cracks appear. 与聚合物添加剂不同，细菌修复可随新裂缝反复发生。

这篇中文题目最接近哪一句？细菌如何建造更坚固的混凝土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？传统混凝土受力易开裂，导致水分渗入并锈蚀钢筋。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 Bacteria Build Stronger Concrete How to cook noodles A maths worksheet

Their metabolic activity forms tiny calcium carbonate crystals inside micro-cracks.

Their metabolic activity forms tiny calcium carbonate crystals inside micro-cracks.

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：Their metabolic activity forms tiny calcium carbonate crystals inside micro-cracks.