What do you think of Bill Gates ? You might think of him as a hard­working 1 of Microsoft or a technological genius , 2 one thing you might not know about him is that he ’ s one of the world ’ s 3 men who left Microsoft to donate billions of dollars and 4 the world by creating new inventions. In 2014 Bill Gates ’ wife , Melinda Gates , 5 Bill to quit Microsoft and work with her to help what Bill Gates 6 the Bottom Two Billion.The Bottom Two Billion 7 a third of the world ’ s population that live with less than 2 US dollars a day.These people 8 live in areas where electricity is rare and disease is far and wide. One of the 9 to diseases are vaccines( 疫苗 ) , which help the body get over the disease.A problem 10 with vaccines because they need to be kept 11 to remain functional.When electricity is rare , it ’ s often very hard to keep refrigerators 12 .One way Gates has proposed is something he calls the “ Super Thermos ”. It ’ s a strong heat­resistant thermos 13 from the same material spaceships use to meet the 14 .This thermos can keep vaccines cold for 50 days. Another problem for the Bottom Two Billion is 15 .From the 1960s to 1980s , there was an agricultural revolution , which has 16 a lot of new ways to produce crops faster.This meant that the world thought the food 17 problem in Africa was gone but this was 18 the case.The way Gates plans to solve this problem is to talk to each farmer one by one , discuss their unique 19 , and give the farmers heartier seeds that grow better on the 20 soil in that area.Doing this will help the farmers grow crops faster and better.