Thanks
They hunted the lion for 3 days...
It doesn't give me a good sense.It is better to be' They were hunting or have been hunting.Do you agree with me?
No. If the whole story took place in the past and has now finished, then there is no reason why you shouldn't say "They hunted the lion for 3 days...."
If you say "They have been hunting the lion for 3 days" that means that, so far, it has been 3 days and they are still hunting it. In your example, that can't be true because you said that they finally caught it.