unaccompanied

形容词 unaccompanied:

1. without accompaniment or companions
2. (of a state or an event) taking place without something specified occurring at the same time

副词 unaccompanied:

1. without anybody else
   同义词：alone, solo

1. He traveled unaccompanied by his parents.
   他没有父母陪伴而去旅行。
2. Children unaccompanied by an adult will not be admitted.
   儿童无成人带领不得入内。