Screenwriters often employ a plot device called a reversal, in which a hero who seems to be making progress abruptly finds himself worse off, and facing a much greater menace.

编剧们都喜欢设计情节反转的桥段，英雄看起来正在取得一些进展，突然发现自己陷入更大的困境中。

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"To me the broomstick was the central plot device and the coolest thing in the movie, " he says.

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Fortunately, this moment is the only example of this as a plot device.

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But it is still fairly new as a plot device, says Kathy Harig, owner of Mystery Loves Company bookstore in Maryland.

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