Hi,�goodnesses!
Yes, that�s right, thanks for nice examples! That�s just the thing I was talking about:
Subordinators of adverbial clauses of purpose "so that; in order that" and "so as to; in order to" are used a bit differently: mind that "so as to" and "in order to" are considered subordinators of non-finite clauses, while "so (that)" and "in order that" are subordinators of finite clauses.
SO THAT =IN ORDER THAT
She bid the present in order that / so that the children wouldn�t find it. = She bid the present, the children wouldn�t find it now.
Advice is given in order that / so that students can choose the best courses. = Advice is given to the students, the students can choose the best courses now.
SO AS to = IN ORDER to
He took the course in order to get a better job. = He took the course, he wanted to get a better job.
He took the course to get a better job. =He took the course, he wanted to get a better job.
He kept the speech vague in order not to commit himself to one side or the other. = He kept the speech vague, he didn�t want to commit himself to one side or the other.
I carried the knife carefully in order / so as not to cut myself. = I carried the knife carefully, I didn�t want to cut myself.
Mind also: The subordinators "so as" and "in order that" can be omitted, whereas "so that" and "in order that" cannot.
I came to see you not (in order / so as) to complain, but (in order /so as) to apologise. = I came to see you, I didn�t want to complain, I wanted to apologise.
She stayed at work late in order / so as to complete the report. = She stayed at work late, she wanted to complete a report.
BUT: She stayed at work late in order that / so that she (the subject is repeated after "in order that" in this case) could complete the report. =�She stayed at work late, she wanted to complete a report.
Though care should be taken when the passive is used, but the sentence becomes clear when the implied �they� is used in the recinstructed sentence with the active.
The land was bought quickly so as not to delay the building work. = They bought the land quickly, they didn�t want to delay the building work.�
Trees are being planted by the roadside so as to reduce traffic noise. = Trees are being planted, trees are meant to reduce traffic.
When "so" is followed by an adjective before a that-clause, but it is another case, as the subordinate clause is not that of purpose but of result with an additional meaning of degree.
The recipe was so simple that even I could cook it. = The recipe was very simple, (that�s why) I could cook it.
He was walking so slowly that before too long we caught him up. = He was walking, (that�s why) we caught him up.
I still can�t say what type of subordinate clause there is in the sentence "The difference was so small as to not be worth arguing about.", though I suspect it to be that of result as well. But I haven�t found any proof yet. The only thing I�d like to quote is that "This is formal and not very common", according to M.Swan.