Which clause is present? English buffs please help!?

1. Ask yourself, how many verbs are there in the sentence?

2. Which is the main verb? (The main thing that happened, not the reason for it happening)

3. What tense is the main verb?

4. What tense is the other verb? Actually it's a gerund, which is an "-ing" verb which is used as a noun or a modifier. (Like "an angry barking dog" where "angry" and "barking" both describe "dog.")

5. What introduces the gerund? "by"

6. What part of speech is "by"?

7. That's what kind of phrase "by talking…" is. "without permission" is the same kind of phrase.

8. So what you have, is one main clause with two subordinate phrases. You can figure out what kind of phrases, can't you?

There is only one clause, "little Johnny violated the classroom rules." "By talking without permission" consists of two prepositional phrases and is not a clause.

A clause must have a subject and a verb.

'By talking without permission' is not a clause. It is two prepositional phrases. 'By talking' is an adverbial phrase modifying 'violated' and uses a preposition and a gerund. 'Without permission' is an adjectival phrase describing 'talking' and uses a preposition and a noun.

The sentence consists of only one clause.

The best answer referred to a gerund but actually there is no such thing I am a language teacher ( including English ) and the ing form is an action-ending not a part of the sentence to classify as a clause.