Wenn ich das gewusst hätte: what would have happened and did not
CEFR B2 · part 2
edumaterial's parts within the level. The European framework does not subdivide them.
lassen: to leave, to have something done, to allow and to be doableOne verb with four distinct jobs, told apart by what sits next to it. Ich lasse den…eine Entscheidung treffen: the verb that lives inside the nounThe fixed noun-plus-verb pairs that replace a single verb, and are the hallmark of…What goes in front of the verb, and what changes when you move itThat the first slot in a German sentence is a decision, not an accident. Ich fahre…Das ist zu machen, das hast du zu machen: obligation without a modalTwo constructions that say what the modals say without using them, and they are…doch, mal, ja, eben: the words that do not translateThe particles that do not change what a sentence says but do change how it lands, which…Reading German aloud: ei, ie, z, v, w, chReading any German word aloud, knowing which letters sound different from how they are…The rule, in three lines
Regret and reproach, which is what this form exists for. You build it with hätte or wäre plus the participle: Wenn ich das gewusst hätte, wäre ich nicht gekommen. And with a modal the double infinitive turns up, the strangest construction in German: Ich hätte kommen können, not gekonnt.
The usual slip. Using the present Konjunktiv II to talk about the past, which mixes two tenses and means nothing. And in the double infinitive, writing the modal's participle: Ich hätte kommen gekonnt is the classic slip, because the modal stays in the infinitive even though the sentence is past. The third is the auxiliary: you pick hätte or wäre by the same test as the Perfekt.
Why it catches you out. English has «if I had known, I wouldn't have come» and marks it clearly. The problem is the shape: English needs «would have» in the second half, German needs only wäre, and the pull towards writing würde gekommen sein is very strong and always wrong.