Charles Babbage was born too soon. He hoped to invent a calculator (计算器).But the technology of his time was too simple. Babbage could not make his dream come true. All his life, Babbage was interested in n_____. For example, he would find out how f______ a pig’s heart beats or make a table to calculate (计算)how much wood a man could saw(锯) in 10 hours. Babbage was also an inventor. Around 1830,he decided to d______ and build a machine for doing simple mathematical calculations(计算).He called this machine the Difference Engine. Making the Machine The Difference Engine was very big and difficult to make. It was made of two tons of steel and gears(齿轮)。While he was building this h______machine, he had an idea for a new machine. Re-inventing the Engine In 1854, two Swedish inventors built a working mechanical calculator. It was based on the Difference engine. Their machine was able to print out different kinds of forms and tables, It was very accurate. Babbage was the first person to come up w_____ the idea of computers. And he is more famous today than he was in his day.