这部电影的贯穿线是主角对家庭价值的不断探索。

The ___through-line of this movie is the protagonist's ongoing exploration of family values.

这部小说的贯穿线将三个主角的命运紧密联系在一起。

The ___through-line of this novel connects the fates of three main characters.

这部电影的贯穿线是主角对正义的执着追求。

The ___through-line of this movie is the protagonist's persistent pursuit of justice.