Present perfect continuous tense. http://www.englishclub.com/grammar/verb-tenses_present-perfect-continuous.htm Have been doing = emphasizes a continuous action in he past, but which is still continuing now. I did = simple past tense. I think the word 着 is how you speak of a continuous action in Chinese. Sorry but it's difficult to explain, its best to learn sentences with this verb tense and compare them winch other verb tenses "I have lessons every two weeks" is a better way to say this. I have been having is putting emphasis on the previous times, even though it is still continuing today. "have been _____ing" is often used in conjunction with "lately": Lately I have been having nightmares. Lately I have been eating more chinese food. Lately I have been going to watch movies at the new theater downtown.