Wrong: Tired of practicing, the orchestra decide to walk out on their astonished conductor.
Correct: Tired of practicing, the orchestra decideS to walk out on ITS astonished conductor.
Why is this the correct version as stated in the guide? Shouldn't the decide be turned into DECIDED (past tense) and not decides, since ASTONISHED is a good clue that all the events happened in the past? Using DECIDES doesn't really even sound correct. If I'm wrong, can someone please correct me on this. Thanks. FYI: completely understand why we change THEIR to ITS since Orchestra is a collective noun (i.e. sing.).
Thanks!