问一下seven-years-old和seven years old有什么区别!

问一下seven-years-old和seven years old有什么区别! he's seven years old. seven years old 划线部分提he's seven years old. seven years old 划线部分提问 seven years old和even-year-old的区别 Do you think doing lots of homework is good for a _____ child? sA . seven years old B seven-years-old C seven-year-old D seven-year-old's ( ) His danghter is ________.A seven years B seven year old C seven years old When I was seven years old i was seven years old when i learned to play basketball 对seven years old提问 Mike is fourteen years old.His brother is only seven years old.(两句合并成一句)Mike _____ _____ his brother's age. Mary is seven years old now .This autumn she S—— her school.横线上填什么单词?最好能把意思说一下,我想了半天都翻译的不通顺. （单复数）那天百度搜到Wake Me Up When September Ends时 看到有句歌词这么写的Seven years has gone so fast 还有句 Twenty years has gone so fast.我想问一下,这Seven years和Twenty years是单数还是复数 是这个句子 She learns English about seven years old.并告诉我为什么. helen is (thirty-seven)years old的适当形式填空 I learn English,I was seven years old I began to learn__a bicycle at seven years old Eve is six years old.Erin is seven years old.合并句子 .Erin is ------- ------- ------- -------- Eve Lucy is eight years old.Lily is seven years old. 合为一句话 my friend saved a _____ boy in the river yesterdayA.seven-years-oldB.seven-years-oldsC.seven-year-oldD.seven years old 英语年龄的表达我知道She is seven years old 和She is a seven-year-old girl 是在正确的但是She is seven-year-old 从语法角度没错的,我不确定.请懂的人来回答,不确定的人不要回复我就是不确定seven-year-old可