“他是第几个学生” 怎么翻译啊？

Which student is he?

Which platform does the Brighton train leave from?
开往布赖顿市的火车在第几站台？

He is the first of several students

Which student is he?他是第几个学生

He is the first of several students。建议你到在线翻译上翻译，比你到网上解决得还要快。