题目

根据下面的对话情景，在每个空白处填上一个恰当的句子，使对话的意思连贯、完整。A: Mom, I don't know thisword. It's difficult.B: Oh, I don't know it,either.?A: But my dad is busy.B: ?A: He is writing a report.B: .A: That's a good idea.I will look it up in the dictionary.B: I'm happy your Englishis improving.A: In fact, my spoken Englishisn't good. ?B: You should have conversationswith foreign friends.A: But it's difficult tofind foreign friends.B: You can go to the EnglishCorner on the square. There are usually many foreign people there.A: ?B: You can start a 若的展开式中第6项为常数项，则n=    ．