应该是第二种，即 ten pounds' weight 另外还可以说成：a/the weight of ten pounds 或者 a ten-pound weight
应该是camera add ten pounds:英文解释如下： It's a common belief among many who take and view photographs that "the camera adds 10 pounds," making anyone in a photograph look heavier than they actually are. This is mainly caused...
are 其单复数取决于前面的数量词pounds Two cups of water on the desk
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