老师你好。我想问下，例句：
Sixty toddlers were each introduced to an adult tester holding aplastic container.
其中each是修饰什么的。是否要还原成主动语态：A introduced each sixty toddlers to an adulttester...。如此是修饰sixty toddlers的，如此正不正确，谢谢老师。
Sixty toddlers were each introduced to an adult tester holding a plastic container.
each 是代词，作 Sixty toddlers 的同位语。像 all, both, each 等代词，作同位语时一般紧靠着同位关系的名词，但句中有 be 动词时，则放在be 动词之后。比较：
The students all study hard.
The students are all hardworkng.
