在上下节课前，你可以向我邮箱发邮件索要新的课件，做好预习。怎么翻译

you can email me for the handout before next class and prepare for the lesson.

You can ask for the new courseware to do the prep
by sending me an E-mail before the next lesson.

courseware : n. 课件

prep : n. 准备功课，预习

You can ask for the new courseware 你可以向我索要新的课件

to do the prep 以便做预习

by sending me an E-mail 通过向我发邮件

before the next lesson 在下节课前

其实如果这是现实中的口语，大可不必这么正式，用这种语法，很随意地说

You can Email me for the courseware to do the prep before next lesson.