________ one foot before the other, slowly and purposefully, the deer walked up to ______ I was _______.

A．Put, where, seated

B．Putting, the place where, seating

C．Put, the place in which, sitting

D．Putting, the place where, sitting

甲建筑工程公司与乙投资商签订的施工承包合同属于( )。

A．双务合同

B．无偿合同

C．实践合同

D．单务合同