Another small wiggle with pinyin input...

I'm studying both 得 dei3 and de2. I normally don't mind that no definition is provided for generative pinyin questions. Unfortunately, with 得 (or any 多音字) it's impossible to know which answer is correct absent context or definition.

EDIT: Is it possible for pinyin questions to have more than one acceptable answer? I have a similar problem with 啊. Though the lesson says 啊 a4, I keep answering 啊 a1 -- valid pinyin, incorrect answer.

EDIT2: Ditto for words where the last character can be neutral or not, depending.