胰岛素瘤是来源于胰岛什么细胞的罕见肿瘤（）
A.D细胞
B.A细胞
C.PP细胞
D.G细胞
E.B细胞
参考答案：E
Being afraid of falling behind the times, he has always been keeping himself ___ of the latest
development of technology. [ ]
A. instructed
B. intended
C. informed
D. demanded
借鉴jiè jiàn
