不定式作表语表示具体动作或将来动作;动名词作表语表示抽象的一般行为. sixteen-year-olds是代词 I'm a sixteen-year-olds sixteen-year-old用作形容词 I'm a sixteen-year-old boy sixteen years old用做表语 eg. I'm sixteen years old
1. be to do 去执行的任务;be doing常规。如:Your job is to take them to the hotel. My job is teaching. 4. sixteen-year-olds十六岁的孩子们 sixteen-year-old十六岁的 sixteen years-old没见过。
呃,系表结构接ing就表示动作的正在进行时,例如你正在看书 I`m reading.而接不定式表示将要做的事,或者目的是什么。 至于年龄的表达,唔 意思是一样的,一般都是sixteen-year-old or sixteen years old 这俩种用法,一般如果是前者可以用作形容词,例如她是个16岁的女孩:she is a 16-year-old girl...