设z1=1-i，z2=a+2ai（a∈R），其中i是虚数单位，若复数z1+z2是纯虚数，则有

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='24593' and id < 2110614 and id<>'2110614' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='24593' and id > 2110614 and id<>'2110614' order by id asc limit 5