Cuando + El Imperfecto de Subjuntivo (When + the imperfect subjunctive)

Question 1

cuando with El Imperfecto Subjuntivo, preceded by a main clause using El Condicional.

Answer 1

What is expressed after cuando is something the speaker sees as a possible thing to happen but with not much certainty, nearly as a conditional sentence with if.

Conditional in main clause + cuando + El Imperfecto Subjuntivo
has a similar meaning to a subordinate clause with “si” (if).

Translating this use of cuando with “when” would be ungrammatical in English, but it is correct to use cuando with this meaning in Spanish.

Ella cubriría todos los gastos cuando él no pudiera pagar su parte.
She would cover all costs when if he couldn’t pay his part.

Question 2

Cuando + Presente de Subjuntivo

Answer 2

When we use cuando with El Presente de Subjuntivo, the speaker sees the action as something with more probability to happen. The level of certainty is higher.

Question 3

I will help you when you behave.

In the example above the speaker believes it is possible he will behave.

Answer 3

Te ayudaré cuando te portes bien.

Question 4

I would help you if [lit:when] you behaved well.

Here the speaker isn’t very certain about him behaving. It is more hypothetical.

Answer 4

Te ayudaría cuando te portaras bien.

Question 5

cuando followed by El Imperfecto Subjuntivo in reported speech

Answer 5

(saying someone said that s/he would do something when something else happened).

The tense used after cuando is determined by the conditional used within the sentence expressing a reported speech:

Direct speech:

Te prometo que te llamaré cuando aterrice el avión.
I promise I will call you when the plane lands.

Indirect speech:

Me ha prometido que me llamaría cuando aterrizara el avión.
He promised he’d call me when the plane landed.

Question 6

He promised he’d call me when the plane landed.

Answer 6

Me ha prometido que me llamaría cuando aterrizara el avión.