Chinese students usually spend _____ the students of the US studying in their free time. [ ]

A. twice as many hours as

B. as twice many hours as

C. twice hours as many as

D. as many as twice hours

工程项目施工合同按照承包工程计价方式可以分为总价合同、单价合同和成本加酬金合同3种，以业主所承担的风险从小到大的顺序来排列，应该是( )。

A．③—②—①

B．①—②—③

C．③—①—②

D．①—③—②