When I finished second grade in middle-school, my family moved to Germany and lived in there in 2 years.
It was totally a "culture shock" what I experienced in Germany, especially in school. I went to German High-School, called 'Gymnasium'.
German education system is different from us. Every pupil in elementary school, who finished 4grade, must enter 3 variation of school of higher grade (Gymnasium-academic high school, Realschule-commercial high school, Hauptschule-junior high school).
It was lucky that I can enter the academic high school in Germany. Not many pupils from elementary school can enter the Gymnasium. Pupils who graduate from Gymnasium are able to enter the university (but not all) and continue to study.
Before hard-studying in university, pupil in Gymnasium have to get strong training how to think of society, how to write the article, how to speak to other people to state my view. So who are at Gymnasium could receive high quality of education.
There are many kinds of Gymnasium in Germany. For example, foreign language Gymnasium, arts, science and the normal one.
I went normal Gymnasium near at my house. Although in normal high-school, you have to choose main foreign language (as special subject of study) between French and English. After finishing 8grade, pupil chooses science course or human knowledge. In human knowledge course you will study Latin.
I was in 'French as first foreign language' class. One year after I chose the science course because I couldn't stand the situation that I was learning 3 foreign languages (German, English and French) at the same time. If I selected human knowledge class (learning Latin), I might be crazy!
The way of teaching foreign languages in Gymnasium was totally different from Korea. First, all of English teachers spoke in their own foreign language in the class. Second, all parts of lessons were made up not only text reading, but also many speaking exercise, last but not least, pupil got many kinds of homework (translate sentences, summarize the text and write my own idea etc.) after finishing every lessons. It was so exhausted to achieve same English knowledge level as my classmate's.
Although my hard studying, my grade were bad. When I got first English exam, I couldn't get any score. I only got the question of my English teacher. She wondered how can I entered the Gymnasium and Why don't I understand the whole lecture of English class.
Other subjects such as mathematic, science were relatively fine. But language, there are impassable differences between I and my German classmates. I felt nervous. 
This gap caused by different education system. When I was middle-school student in Korea, my grades of English was fine and sometimes I won praise that my English is great. But in Germany, I was only a repeater. I absolutely wasn't suited to the new learning method (ask a question, speak loudly to the class, following what teacher say in English, writing exercise in English my own handwriting-In Korea, you only need to select one of 5examples!).
After much consideration, I thought that my bad score of English had caused by lack of grammar. I hated to learn grammar, but I apprehended that without re-learning grammar, I absolutely couldn't follow the class.
Finally, I decided to master the whole parts of English grammar. In summer vacation I spent much time in studying English. The learning material was English textbook in school. Learning this textbook, I was surprising. In the textbook, English grammar were clear at a glance. There were so many illustrations that could help to understand. Many examples were so useful in everyday life and absolutely not complicated.
After studying English grammar, I felt my English leveled up and English class was no more a fear. I got back my confidence and actually, I become a person who can speak to other people in English! It was a miracle, and unbelievable thing before my hard learning of English grammar.
The experience of learning English in Germany is my one of my most unforgettable experience of my life. Sometimes I meet somebody who feels English very difficult, and then I recommend studying my textbook which I used in Germany. I hope that my experience will be helpful to other people who meet difficulty in studying foreign language or plan to study in other country.