1. The new miracle of the medical world is the stem cell, a marvel of human nature in that it can become any of nearly 220 cell types that constitute the human body. 【结构分析】句子主干为：The new miracle of the medical world is the stem cell；“a marvel of human nature”为“the stem cell”的同位语来对其进行补充说明；“in that it can become any of nearly 220 cell types that constitute the human body”为“in that因为”引导的原因状语，其中“that constitute the human body”为that引导的从句充当“220 cell types”的后置定语。
2. Scientists at the Oregon Research Institute in Eugene reported that Tai Chi offers the greatest benefit to older men and women who are healthy but relatively inactive. 【结构分析】句子主干为：Scientists reported that Tai Chi offers the greatest benefit to older men and women；“at the Oregon Research Institute in Eugene”为地点状语；“who are healthy but relatively inactive”为who引导的从句充当“older men and women”的后置定语。
