Hi, When we are talking about a situation that started in the past and still continuing, we use present perfect with the phrase 'since when' in interrogative sentences. And if the situation is in the past and we want to say since when it had continued up to (or probably after as well) another point in the past, we use 'past perfect' with the phrase 'since when' in questions. Examples are: - Since when have you worked in this company?
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.