Task: Question Generation
Input (English): Passage: In his New York City apartment, a young boy named Josh Morrison stares through his telescope at an object falling from the sky. It is a golf-ball-sized metal ball which flies through the window and lands in his fishbowl, quickly draining the water along with the goldfish. He decides to show it at his school's science class presentation.
Some months later a massive fireball crashes into the water near Liberty Island. It is revealed to be a spaceship which resembles a human, controlled by 100 tiny humanoid aliens. Its Captain (also played by Murphy) pilots the spaceship from the command deck located in its head, with the help of his second-in-command Number 2 (Ed Helms), and researcher Number 3 (Gabrielle Union). The spaceship looks very human, and displays numerous superpowers, but the aliens don't know how to make the "ship" act like a human. A superstitious cop named Dooley desperately searches for the alien.
The aliens need to save their planet, Nil, from an energy crisis. They need salt, which they plan to take by draining the Earth's oceans using the metal ball, so they have to recover the ball. After the spaceship is hit by Josh's single mother, Gina Morrison, while driving, the Captain decides to befriend Gina and Josh. He tells them his name is Dave Ming Chang, based on a quick scan of common Earth names. At Gina's home the crew see their missing ball in a photograph taken at the science presentation. After having breakfast with Gina, "Dave" goes to Josh's school where he pretends to be a substitute teacher and eventually is able to talk to Josh alone. Josh tells him that the ball was taken from him by a bully (Nicholas Berman). With Josh's help, Dave takes the metal ball back from the bully.
Output (English): What is the name of the person that pretends to be a substitute tacher?