Some of the lines in this exercise are correct; others have a word which is incorrect. Underline the incorrect word and write the correct one to the right. When man first learned how making a fire, he began to use fuel for the first time. The first fuel he used was probably wooden. As time passed, man eventually discovered that substances such as coal and oil will burn. Coal was not used very wide as a source of energy until the nineteenth century. With the coming of the industrial revolution, it was soon realized that production would double if coal was using instead of wood. Nowadays, much of the huge factories and electricity generating stations would be able to function if there was no coal. In the last twenty or thirty years, however, .the use of coal has declined. As a result, there were changes in the coal industry. It is believed that more people would use coal if oil and gas are not so readily available. There is more than coal enough in the world for man's needs for the next two hundred years if our use of coal will not increase. Unfortunately, however, about half of the world's coal may never been used. Mining much of it would be very expensive even if it was possible to use new equipment. e.g. to make… 1………….… 2………..…… 3………..…… 4……….….… 5……….….… 6………..…… 7………..…… 8………..…… 9……..……… 10…………… 11…………… 12……………