A man in a gray sweatshirt using a power saw.
the guy in the sweatshirt uses the power saw to saw wood for a house
Just because a man is using a power saw does not mean he is using it to saw wood for a house.
He can use power saw not only for wood for a house
A man in a gray sweatshirt using a power saw doesn't imply that he is going to saw wood for a house.