That is the end of the matter once and for all

[Werdna]

Test No. incompl/inter-31 "Life on Mars?", question 5

Because it is coming so close observers are hoping to settle the argument about life on the planet once and for ..........

(a) everything
(b) every
(c) all
(d) altogether

Test No. incompl/inter-31 "Life on Mars?", answer 5

Because it is coming so close observers are hoping to settle the argument about life on the planet once and for all.

Correct answer: (c) all

Your answer was: incorrect
Because it is coming so close observers are hoping to settle the argument about life on the planet once and for every.
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Could you explain it to me, once and for all means once and forever!
Thanks!

[Alan]

This expression is often used to express the idea that whatever is said, is the final answer and after that there will be no further discussion. The comment 'That is the end of the matter once and for all' means simply there will be no more talk about it.
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