Which two words complete the sentence 'Had you () a long time before the bus arrived?'

• A. Been waiting
• B. Waiting
• C. Had waited
• D. Waiting long

Answer: (A)

The sentence is testing the use of a past perfect continuous form to show an action that started before a past moment and continued up to that moment. The correct two words are been waiting, giving Had you been waiting a long time before the bus arrived? Here, had plus been plus the present participle waiting creates the past perfect continuous, which conveys the duration of the waiting up to the bus arriving. This emphasis on a long duration fits naturally with the phrase a long time. The other options don’t fit because waiting alone lacks the perfect aspect, had waited uses the past perfect simple and doesn’t stress the ongoing nature, and waiting long is not grammatical in this position.