Karly always makes sure that someone *has tidied up the classroom*. (tidy up)
(using *everyone* instead of *someone* would be more appropriate here......)
I'll pack my bag after he *has revised* (revise: verb, revision: noun)
2007-08-11 17:11:11 補充:
Another way of saying your 1st sentence:Karly always makes sure that the classroom is tidy.
the second is used the present simple tense:
I'll pack my bag after he revises.
because behind "after or before" we dont use future tense.