— Must I wait here now?

— No, you _____. But you should be back in ten minutes. [ ]

A. mustn't

B. can't

C. don't have to

下列哪项是慢性型ITP患者骨髓象的主要特点（）

A.骨髓增生活跃或明显活跃

B.巨核细胞增多和有成熟障碍现象

C.巨核细胞增多和明显左移现象

D.血小板巨大，异形和染色深

E.巨核细胞减少和无成熟障碍现象