Mary and I have been close friends ______ we met each other 10 years ago.
【原创】Nobody noticed the thief slip into the house because the lights happened to__________.
【原创】I don't remember___________ to the airport that year.
【原创】A man does not know the difficulty of anything_________ he does it personally.
【原创】There is a _________ of 1000 dollars for the return
【原创】Isn't it very kind __________ your parents to do that for us? A. for B to C. about D. of