[Sangetsu]

English is confusing in many ways. A lot of English can be learned in a classroom, but about half is learned by experience through trial and error. Idioms are a good example, as they are often contradictory if taken literally. Knowing when and where to use prepositions also takes time to learn.

Outside the classroom, the two best ways to learn English are through conversation and reading. Since English conversation can often be hard to come by in Japan, I usually recommend reading.