1. [单选题]US and allied officials have said they have seen no credible evidence of civilian casualties（伤亡）from the air campaign,and they say that precision weapons are used in the strikes in an effort to()being hurt．
A. prevent civilians on
B. prevent civilians from
C. Prevent civilians to
D. Prevent civilians in
2. [多选题]机关正式制发公文设计的版头，作者是为了( )。
A. 表明作者单位的意图
B. 表明公文作者的归属
C. 显示该公文的权威性和郑重性
D. 表明该公文的性质和行文方向
