.Only _____ as an interpreter _____ how important it was to practise speaking English.

A．when did I work…I realized

B．when did I work…did I realize

C．when I work…did I realize

D．when I worked…did I realize

项目的( )是指项目的投资者对项目资产权益的法律拥有形式和项目投资者之间的法律合作关系。

A．投资结构

B．融资结构

C．资金结构

D．信用保证结构