Expressions: 'be out like a light' and 'spark out'

[Zorro]

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #75 "At the End of the Day (4)", question 5

More colloquial expressions speak of someone being out like a light, spark out or for a very ......... sleeper dead to the world

(a) big
(b) huge
(c) large
(d) heavy

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #75 "At the End of the Day (4)", answer 5

More colloquial expressions speak of someone being out like a light, spark out or for a very heavy sleeper dead to the world

Correct answer: (d) heavy
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Could you, please expalin the expressions:
"be out like a light" and "spark out"

Thanks

Zorro

[Alan]

Hi Zorro,

These two expressions mean in a very deep sleep so that you are totally unaware what is happening around you. Out like a light suggests that there is no light and spark out suggests that there is not even a spark (a tiny flash) of light. Both clearly indicate that to all intents and purposes that there appears to be no sign of life because the person is in such a deep sleep.

Alan
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English as a Second Language
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