He _____ have finished his work; otherwise, he wouldn’t be enjoying himself by the seaside.

A．should

B．must

C．need

D．can

下列各项风险因素中，( )属于技术风险因素。

A．汇率的变动

B．资金短缺

C．法律及规章的变化

D．施工工艺的落后