存档副本. [2007-04-08]. (原始内容存档于2007-04-08). Mark Twain once stated: For a clever person, it took three months to learn English, it took three years to learn Francais, and took thirty years to learn German.
存档副本. [2007-04-08]. (原始内容存档于2007-04-08). Mark Twain once stated: For a clever person, it took three months to learn English, it took three years to learn Francais, and took thirty years to learn German.