It is in the digging that life is lived.这是个什么从句?怎么超级不好理解?

问题描述:

It is in the digging that life is lived.这是个什么从句?怎么超级不好理解?

换成陈述句是 Life is lived in the digging.
It is ··· that ··· 是强调句的格式