4c2 Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains).
(Some changes in the earth's surface; are; abrupt) (other changes; happen very slowly; ) (other changes happen very slowly (such as uplift; wearing down; )
Some changes in the earth's surface other changes other changes happen very slowly (such as uplift
are happen very slowly wearing down
abrupt