Mi profesora es muy educada y casi nunca interrumpe a sus estudiantes.

Often no. In this sentence, educada mainly means polite / well‑mannered, not “highly educated.”

• Es muy educada ≈ “She is very polite / well brought‑up.”
• For “well educated / with a lot of studies,” Spanish more often uses instruida, con estudios, culto/a, or talks about tiene una buena formación.

So the focus here is on her behavior, not her academic level.

Adjectives in Spanish agree in gender and number with the noun they describe.

• profesora → feminine singular
• Adjective must also be feminine singular → educada

If it were a male teacher:

• Mi profesor es muy educado…

In Spain there is a tendency (not a strict rule):

• maestro / maestra: mainly for primary school teachers.
• profesor / profesora: for secondary school, high school, academy, or university teachers.

So mi profesora suggests a teacher at secondary level or above, or simply the more common term outside primary school.

That a is the personal “a”. In Spanish, when a direct object is a specific person (or people), you normally add a:

• interrumpe a sus estudiantes = “interrupts her students.”
• Without a, it would sound wrong: ✗ interrumpe sus estudiantes.

Other examples:

• Veo a María. – I see María.
• Escucho a mis alumnos. – I listen to my students.

Spanish usually drops subject pronouns because verb endings show who the subject is.

• (Ella) interrumpe… → interrumpe already indicates she / he / it.

You can add Ella for emphasis or contrast, but in this neutral sentence, Mi profesora es… is the natural choice and Ella is unnecessary.

casi nunca = almost never / hardly ever. It’s weaker than nunca:

• nunca interrumpe = she never interrupts.
• casi nunca interrumpe = she almost never / hardly ever interrupts (there are rare exceptions).

In terms of frequency:

• nunca: 0% of the time.
• casi nunca: very low, but not 0%.

Yes. Both are correct and natural:

• Mi profesora es muy educada y casi nunca interrumpe a sus estudiantes.
• Mi profesora casi nunca interrumpe a sus estudiantes y es muy educada.

casi nunca can go:

• before the verb: casi nunca interrumpe
• after the verb with no: no interrumpe casi nunca (also correct, slightly different rhythm; often a bit more emphatic).

Yes, it’s correct, and the meaning is essentially the same: she almost never interrupts her students.

• casi nunca interrumpe
• no interrumpe casi nunca

Both express “hardly ever.” The choice is mostly about style and rhythm; there’s no real difference in everyday use here.

By itself, sus is ambiguous; it can mean:

• his, her, their, or your (usted / ustedes).

In this sentence, context helps:

• Subject is Mi profesora (my female teacher).
• Most natural reading: her students.

If you really need to remove ambiguity, Spanish often uses de + pronoun/name:

• los estudiantes de ella – her students
• los estudiantes de él – his students
• los estudiantes de usted – your students (formal)

mi profesora = my teacher (the one who teaches me).
la profesora = the teacher (some teacher already known from context).

Here, the sentence is about my relationship with her, so mi profesora is natural. Using la profesora would sound like you’re talking about “the teacher” in a more impersonal or context‑given way, not necessarily your teacher.

They are very close and often interchangeable:

• estudiante(s): slightly more formal/neutral; any level of studies.
• alumno/a(s): very common in schools, academies; everyday word for “pupil / student.”

In this sentence you could also say:

• …casi nunca interrumpe a sus alumnos.

Both sound fine in Spain.