In a trial ,a judge must decide which eyewitnesses to believe and which not to believe .
这个句子是: a judge must decide (that) He is to believe which eyewitnesses.的省略句吗?还是a judge must decide to believe which eyewitnesses.是不定时的复合结构?
你的理解不对。
In a trial, a judge must decide which eyewitnesses to believe and which not to believe.
= In a trial, a judge must decide which eyewitnesses he/she should believe and which eyewitnesses he/she should not believe .