Startled

The startled student dropped his books when the school bell suddenly rang.

The startled cat ran away when it saw the stranger.

The startled tourists quickly took cover when they saw the dark clouds approaching.

The startled baby began to cry when the dog barked loudly.

The sudden gust of wind startled the leaves and they rustled loudly.

The startled cat jumped off the couch and ran away.

The startled expression of the cat made me wonder what had startled it.