They found that plenty of kids changed weight categories as they grew, with some bulking up and others thinning out.
他们发现很多的小孩当他们发育的时候改变了重量级别，有些人是变胖，有些人是变瘦。
2
Thinning scissors are used by hair dressers and have serrated cutting edges so that hair is cut at different lengths. This way it doesn't all "bunch up" together.