过去常常做某事;
例句:
Computers are used to do many jobs in the office.
电脑在办公室被用来做很多事.
He seemed to shrink into himself as he used to do.
他看起来和过去一样,做什么事总是小心翼翼.
As one gets old, one does not remember as one used to do.
人老了, 记忆力就不如从前了.