STRATEGI MENGERJAKAN SOAL TOEFL(LISTENING)
(Woman): We've been cosidering various useful hydrocarbon compounds,and today,we're going to look at one of the most useful of all these.That's right,I'm talking about coal.There probably wouldn't have been an industrial Revolution in the eighteenth century without coal.Even today,life would be very different if we didn't have coal.So,where does coal come from?Well,imagine what the earth was like say,300 million years ago-during the Carboniferous period.Much of the land was covered with luxuriant vegetation,especially ferns-ferns big as trees.Eventually,these plants died and were submerged in the waters of swamps,where they gradually decomposed.And we've seen what happens when plants decompose-the vegetable matter loses oxygen and hydrogen atoms,leaving a deposit with a high percentage of carbon.In this way, peat bogs were formed.Then,as time went on,layers of sand and mud are settled from the water over the peat bogs.These deposits grew thicker and thicke...