the amount of carbon dioxide in the atmosphere has risen by more than 30 percent in
问题描述：
the amount of carbon dioxide in the atmosphere has risen by more than 30 percent in
the last 250 years with the half of this increase occuring since 1960 这句是高三课本中的一句 想知道后半句也就是 with the half of this increase occuring since 1960该怎么理解
答
with the half of this increase occuring since 1960这是状语.表示：其中,有一半是自从1960年以来增长的.
整句话翻译：
大气中二氧化碳的含量在过去的250年了增长了30%,其中,有一半是自从1960年以来增长的.