^а _{_собир.} зайти, заглянуть Drop in to see us any time you're in town. Look who's just dropped in! Let's drop in on Jim and Mary while we're in the neighbourhood.    ^б _{_собир.} входить один за другим    ^в выбирать (систему образования и т.д.) Since they have been allowed to choose their own courses, many more students have been dropping in to classes. The organization has asked the city council for more money for the drug treatment centre, where so many young people are dropping in.