That he deduced because the sensors he had installed throughout his mother's home told him that the kitchen door - which leads outside - had not been reopened since 1:36, more than an hour earlier.
At 1:36, she opened the kitchen door and went outside.
在1:36时,她打开厨房门去了外面。
3
For example, when the ratio between the shapes on the two doors was 1:2 (8 versus 16) or 2:3 (8 versus 12), the fish chose the correct door more often than by chance.