Select the correct tense: He had been waiting for the cab.

Answer: Past perfect continuous.

Why this is correct: The sentence uses 'had been' + present participle, which shows an action that was ongoing before another past point.

• Structure: had been + verb-ing (for example, had been waiting).

• Sentence breakdown: He (subject) | had been (auxiliaries) | waiting (present participle) | for the cab (prepositional phrase).

• Use: describes an action that started earlier and continued up to a particular past time or until another past event.

Contrast with other past tenses:

• Past continuous: 'He was waiting' — indicates an action in progress at a past moment but does not place it before another past event.

• Past perfect: 'He had waited' — emphasizes a completed action before another past event rather than the duration or ongoing nature of the action.