they are going to make a film ____a novel by lao sheA basing onB is basing on C is based on D based on

过去分词作定语，可以改为一个定语从句 which is based on，以......为基础。
又如: This is a story (which was) written by Lu Xun.

要选择做作后置定语的 修饰a film 是根据老舍的小说改编的 被改编 是过去分词形式 而不是现在进行时 所以选择d

这里是省略which is的表达方法.
They are going to make a film (which is) based on a novel by lao she.
这里在选项前面的是which is,所以选项里只能用被动语态based on
翻译：他们要根据老舍写的书制作一部电影.

be based on 根据，以…为基础
they are going to make a film (which is可省略) based on a novel by lao she.
你可以把based on ...看成是film的定语或者省略了which is 的定语从句。