in the first place

你当初为什么邀请她？

Why did you invite her ___in ___the ___first ___place?

我们当初就应该讨论这个计划。

We should have discussed the plan ___in ___the ___first ___place.

我们需要理解当初为什么开展这项研究。

We need to understand why we carried out the research ___in ___the ___first ___place.