hind sight in a sentence

1. In hind sight, do I think the 1920s theme was the right thing for Paris?

2. Sometimes one can only tell by hind sight after testing both potency systems on the same patient.

3. That it really was meant as innocent flirtatious joking and only in hind sight did he see how it was wrong.

4. In hind sight, we have to realize that it was apparently never given to us to predict this sign and wonder.