Sequence of tenses and conditionals

Question

This question is about my understanding of the nuances about sequence of tenses and conditionals. I provide some examples and my interpretations down below.

If my interpretations are incorrect or the tenses used in the examples are wrong, please tell me. I also believe many learners can benefit a lot from your answer.

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Scenario 1:

When the clause is about something hypothetical, I think we use the subjunctive form in the noun clause.

(1) If aliens came to earth, I would imagine that the human race were going to be under great danger.

My interpretation: The coming of aliens are hypothetical, so the were is a usage about an imaginary situation aka the subjunctive.

(2) If she were elected president, I would suppose that the country were being on the right track.

My interpretation: It is hypothetical that she were elected president, so the were is a usage about an imaginary situation aka the subjunctive.

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Scenario 2:

When the clause is used to mean something real, I think we use the tense accordingly depending on the context.

(1) If she were me, she would understand what I said/say/am saying.

My interpretation: said means the real past, and say means the present or a habitual thing, and am saying means the thing I am saying now or somewhere around the present.

(2) If I were in her position, I would say to John that I did a bad thing and that I am sorry.

My interpretation: She did a bad thing that offended John, and I talk about what I would do if I were she. Did means that the thing really happened in the past, not the usage about something hypothetical.

(3) If my students studied harder in my class, I would assume their parents must have scolded them the previous night.

My interpretation: They are not studying hard. I think that if they were, it is probably because they were scolded by their parents yesterday, or the night before the time I say this sentence.

Answer 1

In scenario 1, it sounds like you are presently imagining or supposing what would happen in a hypothetical situation, in which case "imagine" and "suppose" should be in the present tense. If, however, you would only imagine or suppose something in the hypothetical situation, then "would imagine" and "would suppose" are correct.

• If aliens came to earth, I imagine that the human race would be in great danger. [Note that the phrase should be "in danger" rather than "under danger"]

• I imagine that if aliens came to earth, the human race would be in great danger.

• I would imagine that if aliens came to earth, the human race would be in great danger.

All three of these sentences mean you imagine (or think) that, in a hypothetical situation where aliens come to earth, the human race would be in great danger. The phrase "would imagine" in the third sentence has an idiomatic meaning, which is discussed in this question. Compare to

• If I were hit in the head with a baseball, I would imagine aliens arriving on earth.

You are not currently imagining aliens arriving on earth, but you would imagine this if you were hit in the head.

Similarly, assuming that you currently suppose that if she were elected president, the country would be on the right track, you could say

• If she were elected president, I suppose that the country would be on the right track.

• If suppose that if she were elected president, the country would be on the right track.

Situation 2, example (1) is a little confusing. The phrase "If person A were person B" comes before a description of what person A would do in a situation that person B is in. In your example: if she were in the situation you are in, is she saying something to herself? I will use a different example to illustrate the use of subjuntive. Suppose your friend plans to buy an electric saw at the hardware store.

• If I were you, I would listen to what the salesperson said/is saying/says.

You are giving your friend advice about what she should have done in the past, or what she should do now or in the future. Since the salesperson did actually say something (or will actually say something), the "say" verb is not subjunctive.

In example (2), you are not actually saying anything to John, you did not do a bad thing, and you are not sorry. So the "say", "do", and "be" verbs should all be subjunctive. Since the bad action happened in the past, we can use the past perfect subjunctive "had done". I would say

• If I were in her position, I would say to John that I had done a bad thing and that I was sorry.

In example (3), the phrase "must have scolded" is the same whether the situation is hypothetical or not. Compare

• My students studied hard, so I assume their parents must have scolded them.
• If my students studied hard, I would assume their parents must have scolded them.