Our playground is not so tidy and beautiful as before. Students must _____ dirty things on it.
A. be stopped to throw
B. be stopped from throwing
C. stop to throw
— Could you tell me ___________? I must prepare for it.
— Well, it will start at 9:00 tomorrow morning. There is enough time for you.
A. why will the speech start
B. when the speech will start
C. where the speech will start