perhaps adv. 也许，可能
"No,we shouldn't wake them. Wait here for a moment. I'm going up to the top floor. I'll be back soon." I waited in his room for what seemed like a very long time. When he came back,be looked worried. "Jane,did you see anything when you opened your bedroom door?" he asked,looking carefully at me. "No sir." "But you heard a strange laugh?" "Yes,I've heard it before. It was like a strange laugh I heard once. I think it is Grace Poole,she laughs like that." "Well,perhaps it was Grace Poole who started this fire. I must think about what to do. I'm glad you're the only person who knows about this. Don't tell anyone! Now,go back to your room."