请问这里的哪里有分词作状语
though typically about two inches taller now than 140 years ago,todays people-especially those born to families who have lived in the us for many generations-apparently reached their limit in the early 1960s.书上说这是状语从句的省略,分词作状语,但是分词作状语不应该是有动词形式的变化的吗?主动用ing 被动用ed 但是这里的从句里面都没有这样的变化啊,从句里的动词都没有看见呢?