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We all know Archimedes was a clever scientist. Using a good method, he showed King Hiero that his crown was not made  of gold. However, do you know Archimedes was also an inventor? In 215 B.C., the Roman army invaded (入侵) Archimedes' home city of Syracuse. He "fought against" the  by inventing a number of "war machines."

One of the machines was the stone thrower. The machine could throw large stones over a great  from the city wall at Roman ships. The Romans were  at the invention. They even stole a stone thrower and then made one for their own use.