His mum ill last week. [ ]
A. isn't
B. wasn't
C. aren't
D. weren't
答案：B
下列肾囊肿的CT表现中不正确的是（）
A.圆形或椭圆形，外形光滑
B.囊肿和肾实质分界锐利，清楚
C.囊肿壁很薄，不能测出
D.囊内密度均匀，接近水
E.注射造影剂，轻度强化
