经分析，某物质只含有一种元素，则该物质                  

A．一定是纯净物

B．可能是化合物

C．一定是混合物

D．可能是纯净物，也可能是混合物

Was it what he said or something ________ he did ________ made her cry?[ ]

A. that; which  

B. that; that

C. that; what  

D. what; that