Before doing this we also did a study of volcanoes since that's where igneous rocks come from.
(we; also did; a study of volcanoes since that's where igneous rocks come from; T:Before doing this) (that; 's; where igneous rocks come from) Context(that 's,List([57, 63))):(igneous rocks; come; )
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we that igneous rocks
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a study of volcanoes since that's where igneous rocks come from T:Before doing this
where igneous rocks come from