A man was waiting for a bus one day, when he noticed a young blonde woman digging a hole...

...and another blonde immediately filling the hole back in with dirt. He watches as they move up the street doing this over and over again. The first blonde digs a hole, and the second one fills the dirt right back in. After a few minutes, he decides to ask them "excuse me, what are you ladies doing?"
"We're working" the first blonde replies.
"Just the two of you?" He inquires.
"Well" the second blonde chimes in, "there's usually three of us, but the girl that plants the trees called out sick"