While working by the terminus of the Donjek Glacier, he witnessed how quickly these changes can take place.
(he; witnessed; how quickly these changes can take place; T:While working by the terminus of the Donjek Glacier) Context(he witnessed,List([53, 65))):(these changes; can take; place)
he witnessed,List([53, 65))
he these changes
witnessed can take
how quickly these changes can take place T:While working by the terminus of the Donjek Glacier
place