We are family: Scientists suspect that a large DNA-based virus took up residence inside a bacterial cell more than a billion years ago to create the first cell nucleus.
病毒跟我们是一家人：科学家认为，十多亿年前一个大的DNA病毒在细菌细胞内居住并形成了第一个细胞核。
2
Out on the horizon, you should see a large blue object. That is the nucleus of the cell.
在地平线上，你应该会看到一个大蓝色的东西，这就是是细胞核。
3
The cell of conventional ICC is usually small and its nucleus occupies a large part of the cell.