Why is tener subjunctive in this sentence?
When you have time you should read this book.
Is translated in my flashcard deck as:
Cuando tengas tiempo debes leer este libro.
Why is this tengas?
5 Answers
El acuerdo siguientes conjunciones adverbiales con el tiempo, y son seguidos por el subjuntivo cuando introducen una situación prevista. Si se introduce una que se considera como terminado o habituales, que son seguidos por el indicativo.
Yo suelo hacerlo cuando nos levantamos. [Indicativo]
Lo voy a hacer cuando nos levantemos. [Subjuntivo]
In general, if the situation in the adverbial clause is viewed as something hypothetical or anticipated —rather than completed, habitual, or factual— then the subjunctive is required.
Sorry, I seem to be having problems seeing the article in English. My browser language is set to Spanish so it keeps translating all pages written in English to Spanish automatically.
The brief explanation is that after adverbs like cuando if the clause refers to future time (anticipated) the subjunctive is required.
It comes our corrrectly when I cut and paste from the English original page. Incorrect when Google translates the page. Sigh! Back to using the browser in English.
Por lo general lo hago cuando nos levantamos. I usually do it when we get up. [Indicative]
Lo haré cuando nos levantemos. I'll do it when we get up. [Subjunctive]
It's because the sentence refers to a moment in the future for which it is uncertain when it will occur.
Cuando tengas tiempo (some future moment, we don't know when), debes leer este libro.
On the other hand, indicative is used when we talk of habitual actions:
Cuando tengo tiempo (every time/cada vez) leo un libro.
I also suggest you read this thread (cuando + subjuntivo):
'Cuando' very often triggers subjunctive, if it's referring to a future event.
Here's a game which will help you with some examples.
If it's used as a question, however, it doesn't trigger subjunctive:
¿Cuándo vas a venir?
Also, if it's used to describe something that has already happened, or is a statement of fact, it doesn't.
Cuando fui a Madrid, mi prima me hizo desayunar chocolate con churros bañados con Nutella. (seriously, I found this one!)
Cuando (él) habla de ti, está feliz.
For two simple reasons.
- Cuando
- Future. (uncertainty)
I don't know much of the grammatical terminology but cuando is a key word that is governed by the subjunctive future, and the future is subjunctive in this case.
Basically, because the event has not taken place yet (does not exist) and the speaker doesn't know if or when (doubt/uncertainty) the listener will have time. If the indicative was used "Cuando tienes tiempo debes leer este libro" the sentence would be fine, it would just imply that the speaker knew with reasonable confidence that at some point within a specific time period (i.e. an employer talking to his employee at work) the listener would have time to read the book.
