如图甲是反射弧的模式图，图乙是反射弧中的某一结构．请根据图甲和图乙分析回答下列问题．

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Some people in Britain and America like to invite friends to dinner at home. But this is more common in America ____ in Britain. Don't worry if your English friends don't invite you home. It doesn’t mean that ____ don't like you.
When you are invited to an evening dinner, ask your friends what ____ you should arrive. It is a good idea to take a small present when you arrive, and it is ____ to say how much you like the house, the room, or the pictures in the room. But don't ask how much these things cost. In this way, ____  you and your friends will have a pleasant get-together.