Not until, Not till, Until；/,a, the ________very recently, scientists didn't believe that the first inhabitants of Tibet arrived only around 4,000 years ago, after the end of_____ most recent Ice Age.
Not until, Not till, Until；/,a, the ________very recently, scientists didn't believe that the first inhabitants of Tibet arrived only around 4,000 years ago, after the end of_____ most recent Ice Age. 【正确答案】：Until; the
