drop in vs fall in vs join in vs visit — phrasal confusion (GiU Units 137–145)

Which is right

Come and see us more often. You can drop in any time you like. ✓

• drop in = visit casually, pop by, no appointment — “drop in any time”, “drop in on your way home”
• fall in = collapse inward (roof) / fall into line (“fall in behind me”)
• join in = participate in something already going — “join in the game / the discussion” (join in + activity, not a person’s house)
• visit = transitive, no preposition: “visit us any time” — ✗ visit in

drop in details

• drop in (on + person) = “I dropped in on Tom” (visit Tom informally)
• drop in at + place = “drop in at the office”
• No object needed: “You can drop in any time” — complete on its own
• Same drop-family: drop by (≈ same, “drop by the store”), drop off (deliver), drop out (quit a course/race)

Source

English Grammar in Use Additional Exercises — Phrasal verbs (Units 137–145). Ebot lesson 2026-09-05.