The speaker raised his voice but still couldn't make himself____.  [ ]

A. hear              

B. to hear              

C. hearing              

D. heard

称取焦炭试样5kg，置于反应器中，在1000士5℃时与二氧化碳反应2h后，经称量知反应后的焦炭质量为3.85Kg，请计算该批焦炭反应性CRI%。