你好， the quality of your recording was a bit difficult to understand: 1) What is the word that came after 'North America' and before the word 'when'? 2) 记住： when there are plural words (ex: Europeans) 必须得说 'zzzz' sound at the end 否则 the word sounds singular (European vs Europeans). 3) 还有 'disease' 也得用 'zzzz' : duh + zzzeeezze. 中国人韩国人通常喜欢用 ‘zh' sound: dee + zheeese . 这是不对。 再来吧，加油 ：）