For theme parks, ______ is the key to _____ visitors, which contributes to the success of running them.
--- How about going hiking this weekend? --- Sorry. I prefer _______ rather than _______.
The teacher asked the students ________.
Could you tell me _______ ?
He asked me _______ I could sing the song “My Heart will Go On.”
Our teacher told us that the moon _________ round the earth.