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

急に警戒する

to become watchful and attentive unexpectedly

予期せず用心深く、注意深くなる

突然用心深くなる

to become cautious or suspicious unexpectedly

突然慎重になること。

to cease an action or movement without warning

to start without warning

突然気づく

to become aware of something unexpectedly

予期せず何かに気づく

突然現れる

to come into sight unexpectedly

予期せず視界に入る

突然思い出す

to recall a memory without warning

警告なしに記憶を思い出す

突然消える

to vanish from sight unexpectedly

予期せず視界から消える

突然姿を消す

to disappear from sight quickly and mysteriously

素早く、不思議なことに視界から消える