she was writing a book last year but i don't know whether she had finished it.为什么不是wrote

问题描述:

she was writing a book last year but i don't know whether she had finished it.为什么不是wrote

从语法上来说可以用,但是意义不同.
was writing a book 表示动作在进行中,有可能持续,从下文看有可能还在写.
用wrote表示:她去年写了本书,显然已经完成了.