未

ADV （表示从未做过某事，尤指惊人的事或坏事）还未，尚未 If you say that you have yet todo something, you mean that you have never done it, especially when this is surprising or bad. 

• She has yet to spend a Christmas with her husband...
  她还从没和她的丈夫一起过过圣诞节。
• He has been nominated three times for the Oscar but has yet to win.
  他已经3次获奥斯卡提名，但从未获奖。