在那个年龄他们不够严肃,They are not ---- ---- at that age.翻译
问题描述：
在那个年龄他们不够严肃,They are not ---- ---- at that age.翻译
答
They are not ---- ---- at that age.有2个空格应该是2个单词了,serious enough
They are not serious enough at that age