Translation:When did you put this rice into the fridge?
The insistence of all the Duolingo courses on the use of the slang term "fridge" is odd to me. I hear "refrigerator" far more often in spoken American English, and almost exclusively in written.
Must be regional. In Australian English, “fridge” is used almost exclusively, both written and spoken and is not considered slang. “Refrigerator” is quite rare, and does sound American when used. Both terms should be considered interchangeable.
We call it a fridge in the UK too.
Interestingly, I can't even hear the word "refrigerator" in my head without it sounding like it's in an American accent.