—We need to learn and work ______ we live.—I think so.
It's foggy today. I'm not sure _______ the highway will be closed soon.
No one knows ____ .
---I seem to be lost. Could you tell me _____?---Sure. You can take the No.3 bus to get there.
----Please tell me ___________________an hour ago.---He rode his bike.
Do you know__________? –He came here by train.