Last week, we had a great time _____ singing and dancing made by ourselves during the

National Day Celebration (庆祝). [ ]

A. to enjoy

B. enjoys

C. enjoyed

D. enjoying

只有损失机会而无获利可能的风险属于( )。

A．投机风险

B．纯粹风险

C．责任风险

D．政治风险