🧭 Grammar B1-36: Expressing purpose

The closing material of the Fleydo B1 grammar series. It widens the A2 infinitive of purpose into a three-machine system: to + verb as the everyday tool when one doer owns both halves of the sentence, in order to / so as to as its formal dress — and the only polite home of the negative purpose, so as not to / in order not to — and so that + subject + modal as the machine the sentence must switch to when the second action gets a doer of its own or needs a modal. The whole topic hangs on one hinge question, who does the second action?, walked through a four-step decision procedure and three worked runs: a same-doer booking, a new-doer map with the modal wound back to could, and a negative purpose in formal dress. The flagship compare puts I left early to catch the train against I left early so that we could sit together, and a note keeps the modal on the clock of the first half: can and will after present, could and would after past, don’t have to for no-need purposes. Practice runs to thirty-one explained items across four sets, six join-the-halves reveal cards, ten sorter situations split by doer, six repairs of real B1 sentences — for to buy, for + -ing, the subjectless so that, the overstretched in order for — and three traps. A 110-word Open Day story makes every purpose phrase tappable, with for + noun kept alive as the A2 shortcut. Teacher notes add a 45-minute sequence, the two-stick-figures board move, the so vs so that boundary and Cambridge B1 Preliminary relevance.