— Have you _____ heard the story?

— No, not _____.   [ ]

A. ever; yet                  

B. already; ever

C. with; with                

D. about; with

已知复数z=（m²+3m+2）+（m²-m-6）i，则当实数m为何值时，复数z是：

（1）实数；  （2）虚数；   （3）纯虚数；   （4）对应的点在第三象限．