"Xi'er, where is your mask?"
"Ah? What mask? Isn't it at your place?"
"Really? I saw someone climbing over the wall last night, and by the way, the mask was gone when I woke up in the morning?"
"How come, the mask is obviously under the bed?" Damn, he was actually tricked.
Intention: When soldiers come, the water will be blocked and the earth will cover it up