Before you can start speaking and writing in English, your brain must get enough correct English sentences. This is obvious . There are two ways to get correct English sentences: listening and reading. Both are good, but reading is much easier than listening. With the help of a good dictionary, you will be able to understand English texts much more easily than movies. If you just read one book in English, you will see that your English has become much better. English phrases will just come to you without thinking when you are writing or speaking. This is true for hundreds of words and grammar structures . If you read in English, you can forget about grammar rules. Throw away your grammar book! You needn't know the rules for the present perfect tense . Instead, read a few books in English, and soon you will feel that "I have seen Paul yesterday" is wrong. The only difference between you and native speakers is that they have heard and read more English sentences than you have. In the writer's opinion, we can grasp English grammar rules   _  .
by reading English books by reading grammar books by writing and speaking by learning grammar rules