why is t-butoxide a stronger base than ethoxide?
The difference between those two is the two extra methyls on the t-butoxide. Care to guess what methyl groups do to an adjacent charge?
i honestly don't have a clue. the only thing relevant i can think of is that a more highly substituted carbon atom will form a more stable radical / carbocation. i'm not sure what this might imply in this situation, if anything.
Read up some more on the electronic effects of the methyl group.
Separate names with a comma.