watchful
adjective uk/ˈwɒtʃ.fəl/ us/ˈwɑːtʃ.fəl/
警惕的；注意的
paying careful attention and ready to deal with problems
Under the watchful eye of their mother, the two boys played on the beach. 那两个男孩在海滩上玩耍，他们的母亲随时看着他们。
She keeps a watchful eye on her boyfriend. 她把男朋友盯得紧紧的。