I lost my chemistry book just now.

我刚才丢了我的化学书。

youdao

He has lost my chemistry book.

他把我的化学书弄丢了。

youdao

I have just lost my chemistry book.

我刚刚丢了我的化学书。

youdao

It depends on the class, like, organic chemistry, for instance, is always open book, open notes.

这要看是什么科目，例如说有机化学总是开卷考试，可以看笔记。

考试应该这么准备 - SpeakingMax英语口语达人

Peek inside the backpack of Zhou Tao, a middle school student at Beijing's Shijingshan school, and you'll find four grammar texts, three math texts, one chemistry book, two books on physics, five on English, three on political science, not to mention an array of extracurricular and tutorial books.

CNN: LITTLE EMPERORS