Some blood types are quite mon，others are regionally ，and still others are rare everywhere.
A. distributed
B. contributed
C. obtained
D. convinced
网友回答
(答案→)A. distributed
B. contributed
C. obtained
D. convinced
解析：此题考查动词辨析。distribute“分散，分布”；contribute“贡献；导致”；obtain“得到”；convince“使某人确信；使某人明白”。句意：一些血型很普通，一些只分布在局部地区，另外还有一些哪儿都很罕见。由句意可知A项正确。