town and city有什麼分別呢?應該如何運用呢?

Town 是 "鎮" 或解作 "小鎮",
City 是 "城市", "城市" 比 "鎮" 大得多.

Hamilton is a town not a city. (咸美頓是一個鎮, 不是城市.)
New York is a city not a town. (紐約是一個城市, 不是鎮.)

雖然town和city 都係指作「城市」，但係都有分別的：
town 通常會用來描述一些小城市、鄉鎮、城鎮，但city
一般都會形容為一些大都市。

Town = a compactly settled area as distinguished from surrounding rural territory [小社區 / 小鎮]
City = an inhabited place of greater size, population, or importance than a town or village [大城市]
例如: My home town is far away from the city.