What causes the poles of the electromagnet in an audio speaker to repeatedly switch directions?
a metal striker that pulls on the magnet
a diaphragm that vibrates around the magnet
a current that rapidly switches direction
a device that opens and closes a circuit

Read the movie summary. two rival magicians compete for fame and success in edwardian london. when their bitter feud begins to escalate, they each resort to more and more dangerous tricks to try to outdo the other, ultimately placing the lives and sanity of those around them in jeopardy. based on this summary, the film is most likely a(n)

The story line remains the same. the kids live in what was then one of the remaining beachfront slums, down the coast from the expensive malibu area. the beach was ruled by surfers, but in the afternoon, when the waves died down, some of the surfers, or their younger brothers, fooled around on skateboards. one day, skip engblom, the shop owner, comes up with a key breakthrough, polyurethane wheels: "they grip." with the additional traction, the z-boys try skating the sides of the big, open drainage canal that runs through the area. then comes a brainstorm: because of a drought, the area's swimming pools were drained. the kids started "borrowing" pools when the owners weren't home, to skate the curved sides.” where did “the lords of dogtown” originally practice their tricks? a. the beach c. an open drainage canal b. empty pools d. none of these

Write a sentence using a gerund phrase with a pronoun subject.