It was along the Mississippi River _____ Mark Twain spent much of his childhood.
—Would you like some more tea? —____ , please.
What surprised me was not what he said but he said it.
---Where did you see him? --- It was in the hotel _____ he stayed.
Your brother promised to help me and ______the next day.
--- Has Li Lei finished his work today? --- I have no idea, but he ______ it when I saw him this morning.