suddenly

to realize or notice something unexpectedly

to experience a quick onset of fear

to become scared in an instant

to be surprised or shocked unexpectedly

突然警觉

to become watchful and attentive unexpectedly

出乎意料地变得警惕和专注

突然警惕

to become cautious or suspicious unexpectedly

突然变得谨慎。

to cease an action or movement without warning

to start without warning

突然意识到

to become aware of something unexpectedly

出乎意料地意识到某事

突然出现

to come into sight unexpectedly

意外地出现在视野中

突然想起

to recall a memory without warning

毫无征兆地回忆起一段记忆

突然消失

to vanish from sight unexpectedly

意外地从视野中消失

突然不见

to disappear from sight quickly and mysteriously

快速而神秘地从视野中消失