你可以说"他在阅读一本英文书"或者"他正在用英语阅读一本书"来表示他正在看书用英语。
来源：这个表达方式源于英语中表示阅读的常用动词"read"，并加上了"in Engpsh"或者"with Engpsh"来表示使用英语阅读。
一些英文例句和中文翻译如下：
He is reading a book in Engpsh. 他在用英语看书。
She is reading a novel with Engpsh. 她正在用英语看小说。
He is studying for his exams by reading textbooks in Engpsh. 他正在通过用英语阅读教科书来复习考试。
She is improving her Engpsh skills by reading books in the language. 她正在通过用英语阅读书来提升自己的英语水平。
来源：这个表达方式源于英语中表示阅读的常用动词"read"，并加上了"in Engpsh"或者"with Engpsh"来表示使用英语阅读。
一些英文例句和中文翻译如下：
He is reading a book in Engpsh. 他在用英语看书。
She is reading a novel with Engpsh. 她正在用英语看小说。
He is studying for his exams by reading textbooks in Engpsh. 他正在通过用英语阅读教科书来复习考试。
She is improving her Engpsh skills by reading books in the language. 她正在通过用英语阅读书来提升自己的英语水平。