You didn't say which meaning of the word you want to be used. A conductor can be the person who sells and checks tickets on a train. A conductor can lead the orchestra. A conductor can be a substance...
Yes. The classic example is for a student to punctuate: Where William had had had had, Charles had had had.
(Where William had had "had had", Charles had had "had")
and your stu stu stu stupid...
Showing possession: When I dropped the cup, I broke its handle.Contraction for it is: When I finish my class this morning, it's the last one until next semester.