There is a slight difference in the first case. The change of position of really changes what is being emphasised by it (slightly): He really is a hero - this statement is: He is certainly a hero. He is really a hero - this statement is: He is very much a hero. We can still win We still can will - these two are identical. The order of "still" changes nothing. They are all valid statements, so it depends on what you're trying to say in the first sentence. In the second the choice is arbitrary. Though in speaking sometimes people will use "we STILL can win" (tonal emphasis on still) as a way of emphasising the remaining hope. Seems a little more natural in that case, but it's really not a big deal :)