Adjunct Condition

Adjunct Condition is a Condition on Extraction Domain which forbids extraction out of an adjunct.

Examples
This condition accounts for the ungrammaticality of sentences like (i) and (ii), where a wh-phrase has been extracted from the adjunct a.

(i)  *Which concert did you sleep [a during t]?

(ii) *How did you leave [a before fixing the car t]?

Link
Utrecht Lexicon of Linguistics