The time adverbial last Saturday tells us that this a single event in the past. Used to is used to describe an ongoing action or state in the past, so you must use the past simple here: He went to.
Habitual aspect
If you've ever written Last summer, I used to go swimming every day when you meant would go — or vice versa — you've hit the habitual aspect's main puzzle. Used to and would both describe past habits, but they have different rules: one needs a time anchor; the other implies the habit has stopped. Mix them up and the meaning subtly shifts.
The habitual aspect marks an action as repeated or routine. English expresses it through the present simple (I walk to work), used to for past habits no longer true (I used to smoke), and would for repeated past actions in a specific time frame (Every summer we would go to the lake).
C1 | Advanced
If you've ever sat through a lecture in English, written a complaint letter, or argued a point in a meeting and come out feeling actually understood — not just tolerated — you've felt what C1 looks like. The level matters because it's where most universities, certifications, and skilled-work environments draw their language line.
C1 is the advanced level in the CEFR framework, demanding fluent and flexible language: inversion for emphasis, mixed and advanced conditionals, formal subjunctive, cleft sentences, and complex nominal phrases — all used appropriately across registers.
Difficulty: Hard
If easy and medium questions are clicking but you still feel exposed in real conversation or formal writing, you've outgrown the basics. Hard material is where the gaps you didn't know you had show up: the distractor that "sounds right", the rule that interacts with another rule, the case where context changes the answer. It's where genuine fluency is built.
The Hard difficulty tag marks upper-intermediate to advanced challenges — typically B2 and above. Interacting rules, edge cases, plausible distractors, and contexts that require genuine understanding rather than surface pattern-matching.