"A goose runs slower than a tiger."
Translation:Gęś biega wolniej niż tygrys.
biega = habitual. biegnie- right now In this sentence both are correct, biega is less ambiguous that it's animals' ability to run, or what happens now.
Biegać is like pływać, jeżdzić, latać - it is either directionless activity right now, ability to do this, or repeated action.
Biec, płynąć, jechać, lecieć - happens at the moment , or ability to do this.( only speed comparisions and numbers come to my mind here - but maybe it's me)
from your link
biegać wyraża pewną regularność, ciągłość; biec dotyczy danej chwili
Thanks, that makes sense. I used biegnie and it was marked wrong. If it means right now then I can see how it could be wrong - the English version "a goose runs" implies habitual or the animal's general ability to run; right now would likely be "the goose is running."
In this context it should be ok, but then maybe not marking it correct is educational. It's an exception, and disturbs neat division. It's like allowing I'm loving it in a lesson about not using love in continuous tense.
There are two verbs which mean the same thing and can be used interchangeably 'biec/biegnąć' and 'biegać'. Both 'biega' and 'biegnie' are equally correct here.
Thanks. I probably should have reported then - I used biegnie and it was marked wrong.