Use until or before

[Sara]

English Language Tests, Intermediate level

ESL/EFL Test #142 "Time clauses: future tense examples", question 2

I want to finish my work ......... we go out.

(a) until
(b) while
(c) before
(d) as soon as

English Language Tests, Intermediate level

ESL/EFL Test #142 "Time clauses: future tense examples", answer 2

I want to finish my work before we go out.

Correct answer: (c) before
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in this cases how can we understand we should use until or before

Sara from iran

[Mister Micawber]

.
Until cannot be used here because finish is a point event, while until requires a continuing situation:

I can't finish until all the parts arrive.
I will keep working until we go out.
.
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Native English teacher at Mister Micawber's