1. I have seen that funny thing before.
2. It was raining when I saw that dog..
- I saw that dog when it was raining?
- I saw that cat whilst it was raining.
Thanks in advance for your help!
I think you used thing as an example. It is OK, but its more natural to use something like cat, dog etc as thing on its own is to vague, in most circumstances, but you can also add words such as; funny thing, strange thing, black thing. But I think you just used it as an example?