To clarify my original comment: what I meant was that sometimes in English a tonal emphasis on the word "and" may serve as an intensifying conjunction. This is often expressed in writing by using all capital or italicized letters (and perhaps I should have used capital letters in my initial comment).
If either of you moderators still disagree with my argument, that's fine; I suppose my error is rooted in a limited understanding of the "i" construct.
Thanks for your time.
I am aware of that. :) Unfortunately, Duo is not very friendly with nuances such as tonal emphasis or using capitals/italics.
Another two factors come to play here:
a) The Golden Rule of Duolingo aka "Translate as closely as possible"
b) We need to teach the difference between "a" and "i", somehow. You might not be aware of it, but Czech uses them quite differently as opposed to other Slavic languages. As a lot of our users are either native speakers or at least familiar with those other Slavic languages, we need to make the difference in usage as clear as possible.
Thank you for the polite discussion and wishing you good luck with conquering Czech! :-)