TASK DEFINITION: In this task, you are given a paragraph, and your job is to generate comma-separated entities present in the given paragraph. Generate entities from a given passage in such a way that (i) they are present in the paragraph, (ii) they are non-duplicate, (iii) they underwent a state change during the process. Avoid creating entities that (i) aren't present in the process paragraph and (ii) aren't significant. 
PROBLEM: Batteries are put in a flashlight. The flashlight is turned on. Two contact strips touch one another. A circuit is completed between the batteries and the lamp. The lamp in the flashlight begins to glow. The reflector in the flashlight directs the lamp's beam. A straight beam of light is generated. The flashlight is turned off. The circuit is broken. The beam is no longer visible. 

SOLUTION: batteries ,flashlight ,lamp ,straight beam of light ; beam ,circuit 

PROBLEM: You speak into the receiver on your phone. Sound waves move parts inside the receiver. Movement causes the magnet inside to produce eletricity. Electricity is transferred through  a wire or cable. A membrane in the other persons phone is vibrated by the magnet in their telephone. Sound is produced. They hear you. 

SOLUTION: Speak ,Sound Waves ,Electricity ,Sound 

PROBLEM: There is a lot of rain. Water levels of a river or lake get higher. Water builds up on the ground. Water covers streets. Water goes into houses. The rain or other source of water stops. Water flows into streams. The rest of the water evaporates. 

SOLUTION:
rain ,water ,streams ,water levels 

