20 years’ 20year’s 20-years’ 20-years 的区别?

20 years’ 20year’s 20-years’ 20-years 的区别? years'和year' s的区别 in 20-year time和in 20 years' time区别 20- years' time跟20 years' time有什么区别? 请教下20 years late.20 years ago.20years later.有什么区别? 他20岁,是he's twenty year old还是he's twenty years old 翻译 in 20 years in 20 years 20 years later year和years的发音区别 year-old和years old的区别 year-old与years old的区别