(1) so that....为了，以便 。引导一个目的状语从句，从句中往往有情态动词。也可引导一个结果状语从句。如：
I left at 5:00 so that I could catch the early bus. Speak loudly, so that they can hear what you say.
He didn't study English so that he lost a chance to work in a foreign company.
(2) so... that....既可引导一个结果状语从句，也可引导一个目的状语从句。
如：The classroom was so noisy that I could hardly study. I got up so early in the morning that I could catch the train.