The metamorphic rocks were originally sedimentary or igneous but were later modified by heat and pressure or other natural processes ( see Lava and Magma ).
(The metamorphic rocks; were; originally sedimentary or igneous) (The metamorphic rocks; were modified; by heat and pressure or other natural processes ( see Lava and Magma; T:later)
The metamorphic rocks The metamorphic rocks
were were modified
originally sedimentary or igneous
by heat and pressure or other natural processes ( see Lava and Magma T:later