The teacher wanted ___ as correctly as possible.

A．that the work was done

B．the work done

C．that the work did

D．the work to do

在当事人意思表示一致以后，仍须有实际交付标的物的行为才能成立，这种合同称为（）。

A.诺成合同

B.实践合同

C.单务合同

D.有偿合同