1. The dog scared the boy.

Question

2. The boy was scared of the dog.
2-1. The boy was scared by the dog.
3. The dog was scary to the boy.
4. The dog was scary for the dog.
5. The dog was scaring for the boy.
6. The dog was scaring to the dog.
(Which ones are grammatical?)

7. The news surprised him.
8. He was surprised at the news.
9. He was surprised by the news.
10. The news was surprising to him.
(Are the four sentences all grammatical? Do you use other expressions related to the word 'surprise'?

Answer 1

1 through 4 are grammatical. 5 & 6 are okay, but seem clumsy. We might say, "The dog was frightening to the boy" instead of "scaring".
7-10 are all grammatical. We might say he was "startled" by the news, "upset" by the news, or any other verb to indicate mild distress or surprise. A thesaurus will give you synonyms for "surprise".

Answer 2

"Surprise" is also a noun. We might say, "The news was a surprise to him."