be terrified at/with

1. 被……嚇一跳
   The small girl was terrified at that big black cat.

   小女孩被那隻大黑貓嚇了一跳。

be terrified of

1. 對……感到害怕
   The child would be terrified of being left alone in the big house.

   這孩子一個人留在那座大房子裡會感到害怕的。