All of A2

The end of the level. Nothing new — but the mix is now wide enough that the first job on every question is deciding which tool it wants.

Six checks: which past · which case · where the verb goes · real or hypothetical · one subject or two · plain or polite.

• Wenn ich das gewusst hätte, hätte ich den Kollegen gefragt, dessen Frau Ärztin ist.

  If I had known that, I would have asked the colleague whose wife is a doctor.

  past counterfactual + dessen

• Die Wohnung, deren Fenster kaputt sind, wird gerade renoviert.

  The flat whose windows are broken is being renovated at the moment.

  deren + present passive

After this, the useful thing is not another lesson — it is using what you have. Reading, listening, and writing short real messages will do more for you now than any new grammar would.