1. He is so distracted in class.

2. He is focused during the class.
3. They are distracting in class.
4. They are distracted in class.
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Can we use all the expressions? Do you have some more expressions-adjectives- you use when many troublemakers make noise in class?

All four are good sentences. Note that "distracted" is a verb. "Focused' is also a verb. "Distracting" is a gerund. None of them are adjectives. Someone making noise in class might be said to be disruptive, disrupting the class. We might say the disruptive or distractive students made too much noise in class.

Sorry to disagree, but in those four sentences, these words are both being used as participles or verbal adjectives: "distracted" and "focused" are past participles, and "distracting" and "focusing" are present participles.

Here's a good webpage that explains and gives examples of English verbs' principal parts:
http://englishplus.com/grammar/00000357.htm

The sentences, as you have written them, though, are good ones, as Reed has said.

Yes, you can use all of the expressions provided. Each expression conveys a different meaning related to attention or disturbance in a classroom setting.

1. "He is so distracted in class." - This means that the person referred to is finding it difficult to pay attention or concentrate during the class. They might be easily diverted or preoccupied with other things.

2. "He is focused during the class." - This indicates that the person mentioned is fully engaged and concentrating on the class. They are attentive and actively participating in the learning process.

3. "They are distracting in class." - This implies that a group of people is causing disruptions or disturbances in the classroom. They might be creating noise, disturbing others, or diverting attention from the lesson.

4. "They are distracted in class." - This suggests that the individuals referred to are finding it challenging to pay attention or concentrate during the class. They might be preoccupied with other thoughts or easily sidetracked by external factors.

Regarding additional expressions to describe troublemakers making noise in class, we can use the following adjectives:

- Disruptive: These students disrupt the class by creating disturbances or causing interruptions.
- Rowdy: This describes students who behave in a loud, unruly, or disorderly manner, making it difficult for others to concentrate.
- Noisy: These students are particularly loud, creating a high level of noise that disrupts the class environment.
- Unruly: This term is used for students who are undisciplined, difficult to control, or disruptive in their behavior.

Remember, when it comes to describing behavior in the classroom, it's essential to use respectful and objective language to avoid generalizations or stereotyping.