Which of the following statements is/are true?

A、Inflectionsarethechangesinyourpitch
B、Thereasonyouwillstammerinthespeakingcontestisthatyouarenotsurewhatyouaregoingtosay
C、Youcanreplacepausesinyourspeechwithfillerwords
D、Youcanmakeyourspeechfluentbyspeakingnonsense