形容詞 watchful:

1. carefully observant or attentive; on the lookout for possible danger
   同義詞：argus-eyed, open-eyed, vigilant, wakeful
2. experiencing or accompanied by sleeplessness- Shakespeare
   同義詞：insomniac, sleepless

1. A watchful nurse tending a critically ill patient.
   照顧一個重病號的謹慎的護士
2. Be sure to be watchful or alert.
   必須留神，千萬要提防。
3. We should be watchful of computer viruses.
   我們應(yīng)該警惕計算機病毒。
4. The guard should be watchful during the night.
   警衛(wèi)在黑夜里也應(yīng)該警醒。

watch.ful

adj.（形容詞）
Closely observant or alert; vigilant:
警惕的：密切注意或戒備的；警惕的：
例句：
kept a watchful eye on the clock.See Synonyms at aware ,careful
注意時間參見 aware,careful

Archaic Not sleeping; awake.
【古語】 不眠的；醒的

【引伸】
watch.fully
adv.（副詞）
watch.fulness
n.（名詞）