The scientist started to explain that the rock was millions of years old.
(The scientist; started; ) (The scientist; to explain; that the rock was millions of years old) Context(The scientist to explain,List([0, 32))):(the rock; was; millions of years old)
The scientist to explain,List([0, 32))
The scientist The scientist the rock
started to explain was
that the rock was millions of years old
millions of years old