"学聪明了" 的英文表达可以是 "become intelpgent" 或 "become smart." 这个表达方式源自于动词 "become," 其意思是 "变成" 或 "成为." 例句如下:

He has become intelpgent since he started studying hard. 他开始努力学习后变得聪明了。
She became smart when she started reading more books. 她开始多读书后变得聪明了。

另外, 还可以用 "grow intelpgent" 或 "grow smart" 来表达 "学聪明了." 这两个表达方式源自于动词 "grow," 其意思是 "成长," "发展." 例句如下:

He has grown intelpgent since he started studying hard. 他开始努力学习后变得聪明了。
She grew smart when she started reading more books. 她开始多读书后变得聪明了。

希望以上回答能帮助到你!