For example, scientists have determined that rain that fell thousands of years ago was, at times, more acidic than rain today.
(that rain; fell; T:ago) (scientists; have determined; that rain that fell thousands of years ago was) Context(scientists have determined,List([13, 39))):(that rain that fell thousands of years ago; was; )
scientists have determined,List([13, 39))
that rain scientists that rain that fell thousands of years ago
fell have determined was
T:ago
that rain that fell thousands of years ago was