_____ the flight to New York will be delayed is ____ I'm especially worried about.

---Jack failed the driving test again． ---The question is_____ we can help him avoid making the same mistake．

The fact is ______ he has not been seen recently.

—Haven't I seen you some place before?—Yes. That's ________ I don't go there anymore.

Mo Yan, this year’s Nobel Prize winner in Literature, believes reading is ______ first stirred his imagination and gave him a way with words.