难怪 (nán guài): (its)不思議ではない （ それは ） 。

No wonder he is so happy today; it turns out he was admitted to Peking University.

No wonder you don't understand; he is speaking a dialect.

No wonder the room is so messy; it turns out the children just played here.

No wonder she speaks Chinese so well; she has lived in Beijing for ten years.

No wonder you can't find that book; it's put on the top shelf.