We have to get to the root of the problem.

我们必须找到问题的根源。

《牛津词典》

We need to get to the root of the problem before we can solve it.

我们需要先弄清问题的根源，然后才能去解决它。

youdao

We need to get to the root of the problem before we can solve it.

我们需要先弄清问题的根源，然后才能去解决它。

youdao