Microvacuum
高真空
🗣️ 情景例句
Oh, we have a lot to be thankful for.
啊，我们有很多需要感谢的事情。
Still waters have deep bottoms.
静水常深。
In his twenties Frank used to make spare parts for aeroplanes.
20多岁的时候，弗兰克曾生产飞机零配件。