Room 1 Room 2 “ O0 OOOO m八m B X Y a The answer(Step 1) Unseen 令 Actions Turn on switch a Wait fora couple of minutes Turn off Switch A Center of speech Technology, Tsinghua University Slide gCenter of Speech Technology, Tsinghua University Slide 9 Unseen A B C X Y Z Room 1 Room 2 ❑ The Answer (Step 1) ❖ Actions: ➢ Turn on Switch A. ➢ Wait for a couple of minutes ... ➢ Turn off Switch A