A. on B. in C. of
A. is B. are C. be
A. at B. about C. of
A. can B. must C. need
A. open B. to open C. opens
A. turn off B. turn on C. turn up
A. turn on B. turn up C. turn down
A. clean B. dry C. quiet
A. put on B. to put on C. to take off
A. mustn’t/can B. needn’t/can C. mustn’t/must