I don't understand those differences.
I cannot understand those differences.
I don't see any difference.
I didn't know that difference.
There is no great difference.
There is no difference between those.
There's no appreciable difference.
I didn't realize the difference between them.
There is no clear difference between those.
I am not sure how to explain about that difference.
I don't know the difference between those.
I couldn't confirm the differences between those.
I can tell the difference of that when I see it.
There must be some kind of mistake.
I don't understand that difference that well yet.
Can you see the difference?
There is no doubt about it.
There isn't any difference in those.
I understood that difference.
You cannot understand the difference with your ears.