Student or Learner
I was taught to use present perfect tense before "since" and "for"
However, is it all right to use present perfect tense before other conjunctions such as "before"?
I have been as busy as a bee before the party.
I have watched the ball game for 2 hours when she came in.
Thanks a lot.
#2 is ungrammatical (--> had been watching...)
#1 is meaningful only if the party in question is a regularly recurring event and, both at certain times in the past and at certain times again in the future, the speaker has been, and expects again to be, busy before it.