In order to know a foreign language thoroughly , four things are necessary. First, we must understand the language when we hear it spoken. Secondly, we must be able to speak it ourselves, correctly with confidence  and without hesitation . Thirdly, we must be able to write it. We must be able to make sentences that are correct in grammar. There is no short way to succeed in language learning. A good memory  is a great help, but it is not enough only to memorize the rules from a grammar book. It is no much use learning by heart long lists  of words and their meanings, studying the dictionary and so on. We must learn by using the language. If we are pleased with a few rules we have memorized, we are not really learning the language. We must "Learn through use". Practice is important. We must practise speaking and writing the language whenever  we can. Learn through use means  _  .
we use a language in order to learn it we learn a foreign language in order to use it we can learn a language well while we are using it both B and C