n so that's what this number is here, we're in the first shell.

带包壳层，The，n，designates，the，shell，它的数在这里，我们在第一层。

youdao

n so that's what this number is here, we're in the first shell.

带包壳层，The，n，designates，the，shell，它的数在这里，我们在第一层。

youdao