首先，你得确认有美人鱼的存在

首先，你得确认有美人鱼的存在

Results (English) 1:

First, you have to confirm the existence of mermaids

Results (English) 2:

First, you have to make sure there's a mermaid.

Results (English) 3:

First of all, you need to make sure there are mermaids