the book is written in german 与 the book was written in germ

哦,是这样的~
1.the book is written in german ：“这本书是德文的.”是现在时的被动语态,强调书的语言（状态）
2.the book was written in german ：“这本书是用德文写的.”是过去时的被动语态,强调书被写这个动作（过程）
呵,区别就是这个,明白了吗 ^ ^