Different kinds of conditional sentences which look similar and confusing

Question

What is the difference in the meaning and uses of following sentences:

1.If Ram does my homework,I will watch a film.

2.If Ram does my homework, I would watch a film.

3.If Ram did my homework, I would watch a film.

4.If Ram were to do my homework(now), I would watch a film.

The sentences above are quite similar to me , I'm often confused with their uses and meanings. Here is my openions about them :

1. 1st sentence suggests that the speaker is sure Ram will do his homework and he will watch film. ( certain Future +certain future)

2.2nd sentences suggests that Ram will surely do his homework and Speaker is imagining that he will watch film. ( certain future + imagined situation of future)

3.3rd sentence suggests that imagining condition ( imagined future +imagined future)

4. 4th sentence suggests that the speaker is quite uncertain and he doesn't expect that Ram will do his homework or It's impossible for Ram to do his homework.Speaker is sad. (Unexpected imagination + expected future)

Now,I would say that i'm puzzled in my opinion. So, please explain me what is the correct meaning and uses of those conditional structured sentences. Please provide a helpfull . Thank you very much in Advance.

Answer 1

Ram will do my homework...

This means that the speaker is certain that Ram will do his homework.

(1,2) If Ram does my homework...

This means that the speaker thinks it is possible, and maybe even probable, that Ram will do his homework.

The second clause is the action that the speaker will take if Ram actually does do it. There is a definite possiblity that this will happen, so you must use a definite second clause ... I will watch a film: you cannot use an imagined second clause ...I would watch a film. Sentence 1 is therefore valid, and sentence 2 is not.

If Ram were an elephant...

The speaker is imagining something that is completely impossible, so the second clause would also have to be imagined- ... I would be able to ride on his back.

(3) If Ram did my homework...

(4) If Ram were to do my homework..

Both of these mean that the speaker is imagining something that it is perfectly possible, so we assume that the speaker has not asked Ram yet, and thinks it's unlikely that he will say yes.

Sentence 3 is imagined because we are talking about a future event but we are using the past tense did.

Sentence 4 is imagined because we use were, which is the subjunctive past of be. Most verbs don't have a subjunctive past, so we use the simple past.

We usually use were to talk about being something (for example late- adjective or a film star - noun) rather than doing something. Here are examples of possible and imagined.

If you are late I will wait for you ... possible

If you were late I would wait for you ... imagined

You can also use were with the noun form a verb- an infinitive: this is what happens in sentence 4, were to do. This gives the same meaning as sentence 3.

With an imagined first clause, you need an imagined second clause, ...I would watch a film. Sentences 3 and 4 are both valid and have the same meaning.

If I were Ram, I would say

You lazy git, you expect me to do your homework while you watch a film?

Ram would be much more likely to agree to do the speaker's homework if the speaker made a suggestion that was advantageous to Ram:

If you do my homework, I will go out and buy pizza for both of us.

This is possible/possible construction. The speaker could also make the same suggestion using imagined/imagined, which is more polite:

If you were to do my homework, I would go out and buy pizza for both of us.