A、February 20, 1909. B、February 28, 1911. C、March 8, 1911. D、March 8, 1914. B短文中提到，第一届美国的国内妇女节是1909年2月28日，成为国际性的节日是在1911年，而日期是在1

International Women’s Day’s celebrated each year on March, 8.(19)Groups around the world use this day to honor the progress of women’s status. They also use the day to call attention to the social, political and economic problems facing women and girls. Among the issues are forced marriage, sexual abuse, poverty and lack of education.(20)National Women’s Day was first celebrated in the United States on February, 28, 1909. The next year,(21)Clara Zetkin, a women’s rights leader from Germany suggested the idea of an international celebration. She said women around the world should set aside one day every year to protest oppression and inequality. She suggested the idea at an International Conference of Working Women in Copenhagen.(20)More than one million people attended events in Austria, Germany, and Switzerland during the first International Women’s Day in 1911. In 1914, the date for the observance was changed to March, 8 in honor of a historic protest for women’s rights. 15 000 women marched in New York City on March, 8, 1908. They marched to demand better pay, shorter work hours, and the right to vote. International Women’s Day is a public holiday in several countries, including China, Russia, Bulgaria and Vietnam.
19. What do groups around the world do on International Women’s Day?
20. When was the first International Women’s Day celebrated?
21. What do we know about Clara Zetkin?