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   Tom and his father are playing in the playground. There is a cat and a dog there. They are playing with a ball together. “I think the cat is older than the dog," Tom says, “I don't think so," his father says. “Why?" “Because the dog looks bigger than the cat " Tom laughs and says, "But I like the cat. It is white and it is funnier than the dog. "Tom's father says, “Dogs are my favourite animals because they are very friendly to me" "Yes, but I like smaller ones. Can we keep one?" Tom says. "Of course," Tom's father says.

设x、y∈R⁺且$\frac{1}{x}+\frac{9}{y}$=1，则x+y的最小值为____ 

下列各句中的修辞手法与例句不同的一项是 (　 　)

例句：虽然冬天的寒意还没有消尽，会场里却到处涌动着春天的热流。