unobserved

形容词 unobserved:

1. not observed
   同义词：unseen
2. not observed

1. It was easy for him to leave the house unobserved.
   他很容易从这座房子溜走而不被发现。
2. He found it is easy to leave the house unobserved.
   他发现很容易从这座房子溜走而不被发现。
3. Hardly ever did they manage to meet unobserved.
   他们几乎从不安排会面，却没有受到注意。