国民生产净值和国民收入的差别是（）
A.直接税
B.间接税
C.折旧
参考答案：B
隧道形成过程中自始至终存在受力状态的变化。( )
By the end of next September, the university ______ 200,000 graduates.
A．have turned out
B．will turn out
C．will have turned out
D．had turned out
