影视英语口语:持保留态度

持保留态度”在英语口语里能怎么说？

蹩脚口语：consider it to be not completely true
地道口语：take with a grain of salt

素材来源：另类童话色彩《灵指神探》
剧情简介：
有一出新的案子，某富豪据称被自己的爱犬咬死，但问题是那狗狗平时很乖很听话，怎么会咬死主人落得要被处决的下场呢？Emerson带Ned潜入停尸间询问死者......

Emerson: How does he look?
Ned: Fine, but my threshold's pretty high, so you have to take what I say with a grain of salt.
Emerson: That ain't a grain of salt: that's one of them blocks they give cows to lick.