“She is doing homework in Engpsh” 表示她正在用英语做作业。
“She” 是主语，“is doing” 是系动词“to be”的现在进行时，“homework” 是名词，“in Engpsh” 是介词短语，表示用英语做作业。
例句：
She is doing homework in Engpsh.
她在用英语做作业。
He is studying for his exam in French.
他在用法语复习考试。
They are reading a book in Spanish.
他们在用西班牙语看书。