Learning about English is not the same as learning English
It is common for people who have grown up studying a language in school, for example in schools in China, to be surprised that they still can’t speak English fluently, even after so many years. They think, “I’ve been studying English for more than ten years – so why is it still difficult to speak to native English people?” The answer is that learning about English is not the same as learning English. It has been argued, convincingly (i.e. 是一个有说服力的论据）that there is a part of our brains that naturally learns language, especially the grammar of language (Chomsky 1983). This means, for children, that if they hear enough language and simply interact (交流) with other people as they grow up, then they will naturally (自然) develop excellent grammar; this happens for all of us in our first language. But when we learn a second language, especially in schools, we often spend more time learning grammatical rules then using the language. And the information – the rules – we learn about the language (such as, use ‘more’ with adjectives of 3+ syllables (3+ 音节)) cannot be easily transferred (moved) into the part of our brain that naturally learns language. They are separate systems in our minds (Scwartz, 1993; Foder, 1983). So if you study a lot of grammatical rules, they will be stored in your long term memory (长期记忆）and you can retrieve (重现出来）this information to help you pass an exam, but it will not be accessible (易接近）to your brain’s language system when you want to suddenly start speaking English.
The solution (答案) is, simply, that if you want to become more fluent in English, then you need to listen, speak, read and write more English. This also means that if you want to improve your English grammar, then it is better to encounter many examples of good grammar then to read a book about English grammar. If you want to improve your ability to write good essays, then you need to read good essays – if you read lots of good essays in English, then you will naturally learn how to write better essays without even thinking about it.
So it may be that much of the time that you have spent learning English has developed your Metalinguistic awareness (元语言学意识) rather than your ability to use English. And it is unlikely that this metalinguistic awareness (元语言学意识) can be easily or directly converted into fluent language skills, but it can help you when you start using the English language, because it can help your brain to notice things when you read essays, or when you are having conversations – and as you notice things while using the language, this is more likely to develop your brain’s language system.