"고기를 자르고 냉동고에 넣었어요."
Translation:He cut the meat and put it in the freezer.
- “The space alien chopped the meat and put it in a freezer.”
- “Mom chopped the meat and put it in a freezer.”
- “The dog chopped the meat and put it in a freezer.”
You get the idea… there is implicit subject, but it can only be determined definitively by context.
The Korean sentence doesn't actually explicitly say "him." It doesn't state who the subject of the sentence is, so without context, it's pretty open to interpretation. The subject could just as easily be "you", "she", "I", etc. If it didn't accept your answer with a different subject, report the question so that they'll see it and fix it!
I have only heard the word "냉동실" in reference to a "freezer." Maybe "냉동고" is more like a dedicated, standing freezer?
Good point, i looked on naver and it seems that a freezer that is attached to a fridge is called 냉동실 so you must be right