CMM 提供了一个框架，将软件过程改进划分成（ ） 个成熟度等级。

A．3

B．4

C．5

D．6

从吃、穿、用等方面举例说明农业与我们生活的密切联系：

吃：                                                                                                                                                。    

穿：                                                                                                                                                。    

用：                                                                                                                                                。