CT主要由（）、（）、（）三部分组成。
参考答案：计算机；显示器；机架
When you come to the fence，you can see a notice _____ there saying "_____ the grass". [ ]
A. putting up; Keep off
B. putting up; Keep away
C. put up; Keep out
D. put up; Keep off
下面哪一种资产组合不属于马克维茨描述的有效边界( )
