阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。
In order to know a foreign language thoroughly （完全地） , four things are necessary. Firstly, we must understand the language when we hear ____ spoken. Secondly, we must be able to speak it ____ (correct) with confidence and without hesitation（犹豫）. ____ we must be able to read the language, and fourthly, we must be able to write it. We must be able to make sentences that are grammatically correct.
There is no easy way to success in language learning. ____ good memory is of great help, but it is not enough only ____ ( memorize) rules from a grammar book. It is not much use learning by heart long list of words and ____ meaning, studying the dictionary and so on. We must learn by using the language. ____ we are satisfied with only a few rules we have memorized, we are not really learning the language. “Learn through use” is a good piece of ____ (advise) for those ____ are studying a new language. Practice is important. We must practise speaking and ____ (write) the language whenever we can.
