Simple
1 Present: We climb the mountains.
2 Past: We climbed the mountains.
3 Future: We will climb the mountains.
. Perfect
4 Present: We have climbed the mountains
5 Past: We had climbed the mountains
6 Future: We will have climbed the mountains
. Continuous
7 Present: We are climbing the mountains
8 Past: We were climbing the mountains
9 Future: We will be climbing the mountains