同学你好，该知识点来自沪江网校《大学英语六级全程备考班【小橙卡专享班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学好：
这样来断句：
The average fluorescence intensity of XIP was significantly higher during/ the first phase, and the first 3 s of the second phase /compared with the remainder of the second phase or active transportation in the PM.

the first phase 和 the first 3 s of the second phase 是并列的成分；compared with ... 是状语。

祝学习愉快！