"Các sở thú"
The final -c sounds silent in các in this recording. Is that standard?
I typed "các sở thủ" - had the tone of the last word wrong. In the past Duolingo showed me the mistake when I checked the answer (you have typos). That feature is gone since the "upgrade". Now I am told my answer is correct. No help with the tone problem. Thanks, Duolingo, for the "upgrade" that makes it makes your app less useful.