1、 This rare and expensive food is actually made from the jellylike saliva that swifts (a type of bird) secrete as they line their nests.
这种稀有而昂贵的食品实际上就是由燕子搭建鸟巢时分泌出的晶状唾液制成的。
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2、 This rare and expensive food is actually made from the jelly like saliva that swifts (a type of bird) secrete as they line their nests.
这种稀有而昂贵的食品实际上就是由燕子搭建鸟巢时分泌出的晶状唾液制成的。
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