题目

Thousands of people began pouring into Pennsylvania from other states．They wanted to buy lottery tickets．The tickets cost only ﹩0．9 each．But that small spending could bring them a reward of ﹩90 million．That was the second largest lottery jackpot（积累奖金）in history． More than 87 million tickets were bought for the Pennsylvania lottery drawing．Those who bought tickets had to choose seven numbers from 1 to 80．The chance of winning was one in 9．6 million．But that little chance certainly didn’t affect ticket sales．In the last few days before the drawing, tickets读图识图，回答问题四大发明是中国的先民们以聪明才智为世界留下的一串光耀千古的足迹，为人类文明进步作出了巨大贡献。阅读下图，结合所学知识，回答问题：（1）根据上面三幅图，请你分别说出与它们有关的三项重大发明。（2）请你结合图三的发明，谈谈它对世界发展的贡献。