Question: I am studying Spanish with the Michel Thomas Method.

It states that in Spanish, `"Had"` is `"había"`:

```
Lo había comprado. / I had bought it.

```

If using `"if"`, `"Had"` becomes `"hubiera"` as this expresses an element of doubt in the word `"had"`:

```
Si lo hubiera sabido, lo habría hecho./ If I had known it, I would have done it.

si hubiera estado allí anoche / if I had been there last night

```

Later on, it gives this example:

```
Si tuviera el tiempo lo haría. / If I had the time, I would do it.

```

I am confused: Why is there no `hubiera` in this last example? I assume `tener (have)` has been modified into `tuviera` to express doubt, but why isn't `hubiera` used?

Answer: 
I'll try to write my comments as an answer.

First, I would say that your assumption is correct, `hubiera` goes into `tuviera`. And that's it. 

On a personal remark, I don't know if this method is helping you but I don't think direct translation is a good idea when learning languages. In particular, subjunctive tenses are kind of dificult to translate directly so you're going to have a rough time with it. I would look for subjunctive tenses in spanish, they are constructed according to rules, it's not random.

What I mean is that you have to use `tuviera` instead of `hubiera` because you're trying to say "another thing" so you do not need `haber` as auxiliar verb. 

You can "tener" A LOT of things (hunger, anger, dissapointment, etc). It does not have to be a real object but yes, if you have/would have a real object then you tienes/tendría o tuviera. Since `hubiera` is working as the auxiliar verb (just as have is used for present perfect as auxiliar verb) it is needed for some verbs that use "hubiera". Since `tener` is not one of the verbs that need auxiliar, you can use `tuviera` (and this is what I mean when I said "you are trying to say another thing") `Hubiera` works for subjunctive as auxiliar conjugation of `haber`, but you also have `haya` and so on check [es.wikipedia.org/wiki/Modo\_subjuntivo](http://es.wikipedia.org/wiki/Modo_subjuntivo)

Also, keep in mind that subjunctive mode is one of the last things that native people learn during elementary school and it is seldom used correctly because of its difficulty.
You don't need "hubiera" because you don't need an auxiliary verb. To have time--in Spanish--idiomatically uses "tener" because in a way you do *possess* time. So what you do is put tener in the imperfect subjunctive, just as you put haber in the imperfect subjunctive in the other sentence.