英语语法分析

Assay of hamamelitannin shows that Witch Hazel bark extract is 31 times richer in hamamelitannin than the leaf extract and 87 times richer than the stem extract.

对金缕梅单宁的研究表明， 金缕梅树皮提取物含量是叶子的31倍，茎的87倍。