Peter was so excited ______ he received an invitation from his friend to visit Chongqing.  [      ]

A. where    

B. that    

C. why

D. when

设在Excel工作表的单元格C2中有公式“=A2+B2”，将C2单元格的公式复制到C3，那么单元格C3内的公式是______。

A．=A2+B2
B．=A3+B3
C．=B2+C2
D．=B3+C3