Are you going to __________ this challenge?(挑战)
No matter ______ the weather is like, you can always find surfers out _____ the waves in Hawaii.
He said that he had met her two years _______.
She said she would return the dictionary to me ________.
The police ____ still not sure ______ the young man killed himself or was killed.
You had better ________some food and drinks before the field trip ________.