建设投资估算有哪些方法？其适用条件各是什么？

____ they all have in common is that they combine fun _____ the opportunity to learn something.  

[ ]

A. What; with      

B. What; on        

C. Which; with    

D. Who; for

----Will you take up teaching as a career after graduation?

---- Hard to say. I ________ go abroad for higher education instead, but it depends.

A．must

B．should

C．might

D．shall

（）不是未来信息化战争的主要作战样式。

A、心理战

B、电子战

C、信息火力战

D、阵地战

光电二极管是利用（）的结构光电器件。

根据沟通基本问题探讨，沟通的（）不对等，沟通的实际效果就难以保证。

A、主题

B、人群

C、主体

D、对象