She moved from butterflies to biochemistry, and her research over the past three decades has revolutionized the study of skin and skin diseases.

VOA: standard.2010.03.29

In the last three decades the lakes have shrunk to less than half of their original size.

VOA: standard.2009.12.16

The Wall stood for nearly three decades, dividing the city and Germany into East and West.

VOA: standard.2009.11.09

Britain's political life has been dominated for the past three decades by two parties - the Conservatives, now led by David Cameron, and Labor headed by current Prime Minister Gordon Brown.

VOA: standard.2010.04.23

Dr.Charles Rabkin and other scientists from the National Cancer Institute looked at gastric cancer rates in the last three decades among a large group of Americans ranging in age from 25 to 84.

VOA: standard.2010.05.12

People in developing countries today are consuming nearly twice as much milk, more than three times as much meat and five times as many eggs as they did five decades ago, according to the FAO report.

VOA: standard.2010.02.22