Reaction boundary
[机] 反应曲线
🧩 词语组成解析
🗣️ 情景例句
They also ask questions like Where do you come from? and Where do you live?.
他们也会问“你从哪儿来？”，和“你住在哪儿？”这样的问题。
Your pronunciation is excellent.
你的发音很好。
and so the tools of long ago have remained when even the bones of the men who made them have disappeared without trace.
因此，尽管制造这些工具的人的骨头早已荡然无存，但远古时代的石头工具却保存了下来。