She is considering when she should join the eco-tour.
-> She is considering when to join the eco-tour.
We were discussing the community's future plans when the power went out.
-> While we were discussing the community's future plans, the power went out.
I've never seen a coral reef before. I want to see it someday.
-> I wish I had seen a coral reef before. (or) I wish I could see a coral reef someday.
If you concentrate on one task, you can complete it more efficiently.
-> The longer you concentrate on one task, the more efficiently you can complete it.