30. 偽膜性腸炎是由下列哪一個病原菌引起? (A) Clostridium difficile (B) Entamoeba histolytica (C) Vibrio cholera (D) Cytomegalovirus

1. Malignant tumors are characterized by the following findings, except (A) Tumors remain localized, will not spread to other sites, and are amenable to local surgical removal (B) Tumors can invade and destroy adjacent structures and spread to distant sites (metastasize) to cause death (C) Lack of differentiation (D) Pleomorphism (E) Mitoses