2.He teaches thermodynamics at the university. [ THIS IS WRONG THOUGH THE MAN IS ALIVE AND WORKS AS A TEACHER.]

3.He taught thermodynamics at the university. [ This is the correct one.]

4.He is teaching thermodynamics to the students who follow the mechanical engineering course. [ This too is correct.]

Now the man is dead. I am going to the funeral.

5.He had taught thermodynamics at the university. [ Is this correct? I doubt it very much.]

A fictitious example:

6.He drives buses. [ He is still alive.]

7.He drove buses. [ After his death we could use this form. If someone asks about

the dead man 's profession, the 6th sentence is a correct one. However, the verb 'teach' is a tricky one.]

My question is on how to use the verb teach when the teacher/professor is dead.
1 2
I would used the following:

teaches (now)

used to teach (past, but he's still alive)

taught (past, now deceased)

These are not hard and fast rules, but they seem to fit the examples you've supplied.
If the professor is dead, then the past simple 'taught' is the standard form to use ("He taught thermodynamics at the University"). However, if he stopped teaching thermodynamics at the University before he died then it would make better sense to use the verb's participle form, as part of a past perfect contruction ("He had taught thermodynamics at the University before teaching biology/retiring in 2006"). In this case, you would be referring to the past before the past, sort of...
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I thank both of you for the replies.

1.He is teaching English at ...

We don't say the above.

2.He taught English at ...

We say the above.

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Now the man is dead. Anonymous say the following is correct.

He taught English at ...

I have some difficulty in digesting the above.

After his death, as Anonymos says the following is correct.

He had taught English at the University before teaching biology/retiring in 2006")

The above is a proper past perfect sentence. The words 'had taught' look odd to me.

I had worked as a toilet cleaner before retiring in 1970. [CORRECT]

I had taught English to foreign students before retiring in 1970. ?

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Let us say he is a driver. If someone asks about his job, the followng is fine

He drives buses.

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After his demise the following is correct.

He drove buses.

The verb taught is a bit different. To be candid, I don't know the flaw in the first sentence.
There is no flaw in the first setence. I don't know why you think "He teaches English at the local university" is wrong, as long as the man is still alive and still teaching.

Where is Dr. Parker doing these day?
Oh, he's teaching part-time at the community college while working on his novel.

What does your husband do?

He teaches English at the local community college.

Both of these are fine!
Thanks Grammar Geek

I have learnt in that way. The principal of the school says that English is taught at our school.

He won't say we are teaching English at out school.

I have learnt to write this way.

http://dictionary.cambridge.org/dictionary/british/teach?q=teach
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I'm not sure how that link prohibits the use of "He teaches English."

Perhaps some British English speakers will comment. I am completely unaware of this being a difference in American and British English.

She not only teaches us German, but she teaches us about German culture and makes us German food. We all want to go to Germany now! -- You are saying that you were taught that this was incorrect?

If English is taught, who is teaching it?
Grammar Geek

I know an Englishman who trains me with at the gym. He trained with me today at the gym and I discussed this with him. I have trained 100 minutes today.

He said the following:

He teaches English at ABC school. [ CORRECT]

However, the principal of the school says the following:

5. English is taught at ABC school. [CORRECT]

Do you agree with the 5th sentence?
#5 is a correct sentence, but it should be used to say what is taught to students there, not who teaches it.

A: So, all the classes are held in English at ABC school?

B: No, English is taught there, but we hold our classes in French. Well, except the advanced English learners, who have their classes in English.

If you want to talk about the teacher, and you say "English is taught there by him," you have a truly horrible sentence!

I agree with your friend from the gym that "He teaches English at ABC school" is entirely correct.

I wonder why your principal objects to it. It's puzzling!
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