Hi^^ I'm studying the usage of せい and せいで, and it says (I'm using "Dictionary of Intermediate Japanese Grammar" as main reference) that it cannot be used to express a reason :

1)宿題がたくさんある　*せいで　パーティに行けない。 2)誰も手伝ってくれない　*せいで　一人でやらなければならない。

(in both cases it uses から・ので・ために)

I'm not clear on these sentences: can't we consider the presence of a lot of homework as a cause for not having time? [or is it related to the fact that maybe homework are a "controllable" thing? ] what is the difference between n°2 and, say, 私のせいで作業が遅れてしまった。[other than the past tense]?

I would really appreciate if you could also give me some other examples of sentences where I can't use it. Thank you in advance.

Hi^^ I'm studying the usage of せい and せいで, and it says (I'm using "Dictionary of Intermediate Japanese Grammar" as main reference) that it cannot be used to express a reason :

1)宿題がたくさんある　*せいで　パーティに行けない。
2)誰も手伝ってくれない　*せいで　一人でやらなければならない。

(in both cases it uses から・ので・ために)

I'm not clear on these sentences: can't we consider the presence of a lot of homework as a cause for not having time? [or is it related to the fact that maybe homework are a "controllable" thing? ] what is the difference between n°2 and, say, 私のせいで作業が遅れてしまった。[other than the past tense]?

I would really appreciate if you could also give me some other examples of sentences where I can't use it. Thank you in advance.