I'm sorry, but you'll have to start over. = I'm sorry, but you'll have to start (all) over again.对不起，但是你得重做。

She saw her divorce as an opportunity to start (her life) over.她把离婚当作开始（新生活）的一次机会。

In the spring, the eggs hatch, and the cycle starts over. = The cycle starts (all) over again.春天，蛋开始孵化，新的一轮循环又开始了。