In order to know a foreign language thoroughly(彻底地), four things are necessary. Firstly, we must be able to understand the language when we hear it. Secondly, we must be able to speak it by ourselves correctly, with confidence and without hesitation(犹豫). Thirdly, we must be able to read the language. Fourthly, we must be able to make up sentences that are grammatically correct. We must know how to put sentences into paragraphs in order to write a good letter or article.
There is no easy way to succeed in learning a foreign language. A good memory(记忆力)is of much help, but it is not enough to simply remember rules from a grammar book. It is no much use learning long words and their meanings by heart.
We must learn not only words but also the use of them in sentences. We must learn by using the language. "Learn through using" is a good piece of advice for people to study a new language. Practice is very important. We must practice speaking and writing the language whenever we can.