"This boy graduated from elementary school at the age of 11" 可以用英语表达为 "The boy graduated from elementary school at the age of 11."

"Graduated" 是 "毕业" 的意思，来自英语单词 "graduate"，意思是 "to complete a course of study at a school, college, or university"。

例句：

I graduated from high school in 2000. (我于2000年从高中毕业)
She graduated from college with a degree in engineering. (她以工程学学位毕业)

另外，"elementary school" 是 "小学" 的意思，来自英语单词 "elementary"，意思是 "relating to the first stage of education, typically for children between the ages of about 6 and 11"。

例句：

He went to elementary school in the same town where he grew up. (他在他长大的那个城镇上读小学)
She taught at an elementary school for five years before moving to a middle school. (她在一所小学教了五年课，然后转到了一所中学)