Breakdown of Медведь, нападающий на врага, выглядит страшно.
на
on, at / by (transport) / to (a place) / to (in answer to)
страшно
scared / scary
медведь
bear
выглядеть
to look, to appear
Questions & Answers about Медведь, нападающий на врага, выглядит страшно.
How exactly did we get нападающий from a который clause?
If we wrote this with a clause, it would be Медведь, который нападает на врага, выглядит страшно. Because the bear is doing the attacking (active voice) and it is an ongoing action (present tense), we take the "they" form of the present tense verb (нападают), drop the -т, and add the active participle ending -щий. It takes the masculine, singular, nominative form to exactly match the noun it describes, Медведь.
Why are there commas around the phrase нападающий на врага?
In Russian, when a participle phrase (the participle plus any extra words attached to it) comes immediately after the noun it describes, it must be enclosed in commas. If you moved the entire phrase before the noun to say Нападающий на врага медведь выглядит страшно, the commas would disappear.
Why do we say нападающий на врага with the preposition на, instead of just using the noun directly as an object?
The root verb нападать (to attack) dictates the grammar here. In Russian, you cannot attack someone directly as a simple direct object; you attack "onto" them. Therefore, нападать and its participles always require the preposition на followed by the accusative case.
Why does the sentence end with the adverb страшно instead of an adjective like страшный or страшным?