问prep1-203的过去完成时

sunnygirl_jj

In late 1997, the chambers inside the pyramid of the Pharaoh Menkaure at Giza
were closed to visitors for cleaning and repair due to moisture exhaled by tourists, which raised its humidity to such levels so that salt from the stone was crystallizing and fungus was growing on the walls.


A. due to moisture exhaled by tourists, which raised its humidity to such levels so that salt from the stone was crystallizing

B. due to moisture that tourists had exhaled, thereby raising its humidity to such levels that salt from the stone would crystallize

C. because tourists were exhaling moisture, which had raised the humidity within them to levels such that salt from the stone would crystallize

D. because of moisture that was exhaled by tourists raising the humidity within them to levels so high as to make the salt from the stone crystallize

E. because moisture exhaled by tourists had raised the humidity within them to such levels that salt from the stone was crystallizing

答案是E

这道题我选对了，但我不明白正确选项中的过去完成时是怎么回事，如果从时间上讲raise应该在exhale的后面，所以，至少应该是并列的一般过去时啊？

cx_ding

exhale是过去分词作定语修饰moisture。
原句1997年，关闭了（过去时），在关闭以前怎么怎么... 所以用过去完成时。