承包人请求发包人支付工程款和报酬的前提是( )。
A．垫付款 B．预付款 C．工程造价 D．工程量的确认
参考答案：D
It's_________ to work out this problem. You needn't go to the teacher.[ ]
A. enough easy
B. easily enough
C. easy enough
D. very easily
CRH2动车组车钩高度为（）。
A.1100mm
B.1000mm
C.880mm
