how can we tell whether the sentence means; the lion eats the chicken OR the lion IS eatING the chicken
You can't, Romanian does not have two present forms. Both English translations should be accepted.
In both cases it should be "a lion," not "the lion."
TY for your prompt reply.
It should but it isnt...
You should be able to understand it from the context (if it is given, which it normally is) and/or the words that indicate temporal characteristics of the action (like, 'now', 'usually' etc.).