twelve-year-oid
用横杠将数词与名词分开是不需要加s的
而且 修饰的是名词,
如果twelve-year-old放句末,那么将变成twelve-year-oid
例：She is a five-year-old girl=The girl is five years old
简单一点就是“-”="s”
listen to意为“听”是修饰人的 hear of意为“听说过”,修饰事情
like to do sth没有 like to be sth这个句型
加油哦,相信你一定能学好英语的