thirty和fifty读音不相同。
thirty
美 [ˈθɜrti] 英 [ˈθɜː(r)ti]
n.三十几；三十年代
num.三十
网络:卅；三十个；三十的
复数：thirties
例句:He had been a soldier since he was seventeen, and planned to stay in the army till he was thirty.
自从他十七岁以来，他就是一名士兵并且还计划呆在军队里直到他三十岁为止。
fifty
美 [ˈfɪfti] 英 ['fɪfti]
num.五十
n.五十几；五十年代
adj.许多的
网络:半百；五十个；五十的
复数：fifties
例句:Logistics performance is happening around the globe, twenty-four hours a day, seven days a week and fifty-two weeks a year.
物流运作一天24小时、一周7天、一年52星期在全球发生。
