| Structure | When to use it | Form | Typical errors & how to fix | |-----------|----------------|------|----------------------------| | | Past habits that no longer happen | used to + base verb | Forgetting the “to” → remind students “I used to live in a village.” | | be used to + -ing / noun | Something you are accustomed to now | be + used to + gerund or noun | Mixing up the two forms – do a quick contrast chart. | | must vs. have to | Must = personal rule; have to = external rule | must + base verb / have to + base verb | Over‑using must – give examples of each. | | comparatives (more/‑er) | Comparing two things | more + adjective (long) or ‑er (short) | Incorrect word order – practice with city‑related adjectives (e.g., “more crowded”, “cheaper”). |