Too many cognates in Gen 1 which makes it really hard in Hard mode, where if you do not pick the one they wanted specifically, they mark you wrong. Things like Slowbro | Machamp, Poliwag | Ditto, Caterpie | Goldeen, Charizard | Rhyhorn, Poliwhirl | Wigglytuff, Doduo | Diglett, Omanyte | Machop, etc... I think I'm missing some, but some of the others that sound similar I could somewhat distinguish (Cloyster | Fearow, Chansey | Pidgeot, Venusaur | Dragonite), but these are somewhat tough.