"여우가 쥐를 가지고 있어요."
Translation:The fox has a mouse.
Yeah this is pretty ridiculous. When you place the cursor over 가지고 있어요, the hint literally says "is carrying."... but when you type in "The fox is carrying a mouse" it flags it as wrong.
The fox has a mouse would typically be said as just "여우가 쥐를 있어요" but apparently that gets flagged too.
가지다 = to carry when this verb is employed in a stative sense as to have (in ownership)/own; to possess; to be with child (pregnant) etc.
e.g. to carry a scar for life; to carry a health warning; to carry twins etc.
When 'to carry' is used as a dynamic verb which involves an action or movement then probably some other korean verb will be put to use (e.g 들다).
e.g: to carry guns; to carry passengers; to carry electricity across town; to carry diseases etc.
This is probably why DLG has chosen the verb 'to have' as translation for 가지다. This is to avoid any misunderstanding.
1) In English, "Have" (as in "possess"/"own") does not have a progressive form.
2) If wished to maintain the progressive form of the Korean sentence in this case, perhaps "is holding" is the nearest translation. After all, the short form of 가지다 is 갖다 ( - hold, have in one's possession).