监视者

例句：

1. 1. Thesecurity guard was monitoring the entrance of thebuilding.
   保安正在监视大楼的入口。
2. 2. Theteacher monitors the class to ensure everyoneis following the rules.
   老师监督课堂以确保每个人都遵守规则。
3. 3. The monitor kept an eyeon the students during the exam.
   监考老师在考试期间一直盯着学生。