Translation:How cute that panda is!
I haven't come across "那只" before. It doesn't seem to be considered a two-character word but it also doesn't seem to translate directly into English word-for-word like you might expect it to if it's not an idiom. "That only panda how cute!" - So how should we think about "那只"?
Does it refer to a specific panda, "that one"? Or does it refer to pandas in general. If the latter then both "The panda is very cute" and "Pandas are very cute" should be accepted but currently the latter is marked wrong.