Now that you have a job, you must exert (努力) yourself in ______ you do at work.
____ was very ______ that little Jim wrote the letter.
What is it _____ his daughter needs most?
Who was it _____ saved the drowning girl?
“How was ______ they discovered the entrance to the underground palace?” “Totally by chance.”
___ that caused him to serve dinner an hour later than usual.