Which verb tense is used in the sentence "I wished I had not taken that wrong turn"?

The sentence "I wished I had not taken that wrong turn" utilizes the Past Perfect tense. This tense is used to express an action that was completed before another action in the past. In this case, "had not taken" indicates that the action of taking the wrong turn occurred before the act of regretting it, which is highlighted by the verb "wished."

The Past Perfect is notably effective in conveying the speaker's reflection on a past event—indicating that the speaker has a sense of regret about a decision made prior to that moment of reflection. It sets up a clear temporal relationship between the regret (the act of wishing) and the earlier action (the wrong turn).

The other options do not fit the context of the sentence: the Future Perfect Continuous involves actions that will have been ongoing until a certain point in the future, the Present Continuous describes ongoing actions in the present, and the Simple Past reflects actions completed in the past without any further relation to another past action. Thus, the use of Past Perfect is uniquely appropriate here to convey the speaker's sentiment.