adj.警戒的；警惕的

We must keep an vigilant eye upon imperialism. 我們必須對帝國主義保持警戒。

A pilot must be vigilant at all times. 飛行員必須隨時保持警惕。

The British Prime Minister Gordon Brown has urged people to be vigilant against the potential terrorist attack. 英國首相戈登.

n.義警警員；治安團體的成員

adv.警惕地；留心地