If the blocking is irreversible, you can't define a threshold level and so the effect is cumulative.

如果阻塞是不可逆转的，则无法定义阈值水平，因此效果是累积的。

If the effect is reversible, it depends on the concentration and so you can define a threshold level.

如果效果是可逆的，它取决于浓度，那么你就可以定义一个阈值水平。

" For consciousness to evolve, a brain with a threshold level of complexity and capacity is required, " he added.

“想要进化形成意识，大脑的复杂性和容纳度需要达到一定的阈值，”他补充道。

Yet, as you know, ladies and gentlemen, here in India, basic literacy is still below the threshold level of 75% literacy.

然而，女士们、先生们， 正如你们所知，在印度，基本识字率仍低于 75% 的门槛水平。

There are groups of patients who have a threshold level of smoking whose lives can be saved by doing a screening study, which is a CAT scan.

有一些吸烟量达到阈值的患者群体，通过筛查研究可以挽救他们的生命，也就是计算机X射线轴向分层造影扫描图。