Definition
Used to clarify or restate something in a more precise way; in other words.
表示更精确地说；换句话说。
This project requires a significant investment, that is to say, we need to find new sources of funding.
这个项目需要大量投资，也就是说，我们需要找到新的资金来源。
She wasn't really angry, that is to say, she was just a little disappointed.
她并不是真的生气，也就是说，她只是有点失望。
He needs more practice, that is to say, he should spend some time practicing every day.
他需要更多练习，也就是说，他应该每天花些时间练习。