TASK DEFINITION: In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.
PROBLEM: Michael Westen: Creating an explosive device in the field requires a strong knowledge of chemistry and the ability to improvise with whatever equipment happens to be lying around ... An old fire extinguisher makes an ideal compression chamber . Add some metal shavings and the right cleaning supplies , and you can serve up a bomb that can blast through a cinderblock wall .
Fiona Glenanne: Why is it you can never find a good sodium hydroxide solution when you need _ one _ ?

SOLUTION: solution

PROBLEM: Kevin Ryan: Hayley .
Javier Esposito: What happened ? Did you lose a bet and now Castle gets to drag you everywhere he goes ?
Richard Castle: Quite the contrary . Hayley actually wanted to watch me solve yet another murder .
Kevin Ryan: You mean help solve . You help .
Javier Esposito: Yeah . Remember , bro , you can not solve a homicide without us .
Kevin Ryan: But we sure as hell can solve _ one _ without you .
Hayley Shipton: Really ? Because on the ride over here , Rick was bragging about how the NYPD ca n't close a case .
Richard Castle: Eh , those were just jokes that ... out of context , it 's not as funny . I was rolling my eyes when I said it .
Richard Castle: Thank
Richard Castle: you for stabbing me in the back .

SOLUTION: homicide

PROBLEM: Poet: Every moment requires a purpose .
Lwaxana Troi: No , it does n't .
Poet: Every purpose requires a plan .
Juggler: He does this every day , usually while everyone 's food is getting cold . It 's rather boring .
Poet: The higher , the fewer
Lwaxana Troi: Well , that 's a conversation stopper if I ever heard _ one _ .

SOLUTION:
stopper