I cannot understand these.
1st
- We didn't win our first four games, but now we are second in the league. (o)
- We haven't win our first four games, but now we are second in the league. (x)
2nd
- For the last half hour I have been watching some dolphins near the boat, and I feel really happy to be here. (o)
- For the last half hour I have watched some dolphins near the boat, and I feel really happy to be here. (x)
Why each first line is correct?