The majority of samples have no residues or just a fraction of the tolerance level.

大多数样品没有残留物或者只是公差等级的一小部分。

All of these effects relate to taking a small amount of heroin, depending on the tolerance level of the user.

所有这些影响都与服用少量海洛因有关，具体取决于使用者的耐受程度。

The difficult case, the presentation reads, is someone  who has a high tolerance for alcohol but doesn't display the traditional symptoms due to their tolerance level.

演示文稿中写道，最困难的情况是，某人对酒精有很高的耐受性，但由于其耐受水平而没有表现出传统的症状。