C51 A stranger

Within a second, I tried to recall who had not returned from the outside, but all of them, including Chen Ming, had returned.

After a few seconds of silence, Xiaoyu looked at me and mouthed, "What do we do?"

I thought for a moment. The way he knocked at the door obviously meant that he thought there was someone in the room. Furthermore, our conversation was quite loud. They must have heard it