用所给单词的适当形式填空，未提供单词的根据上下文填入适当的词。
English teachers may not teach the debate (辩论) ____ they think it is too difficult for their students. But the debate can be a powerful tool. It can help students learn to speak naturally and to listen ____ (careful). Professor Charles Lebeau ____ (teach) English and debate in Japan. He wrote a book ____ (call) “Discover Debate”. The book helps English learners understand how ____ (carry) on a simple debate. When teaching the debate to English ____ (learner), Mr. Lebeau begins with “controlled practice”. Students work in pairs to practise ____ (say) opinions and giving reasons in short conversations. They learn to identify opinions about everyday topics, such as sports stars, food, weather and habits. In the next stage, students tell their argument (论据) They have to do some talking, ____ not too much. The ____ (three) stage is answering the other team's argument. Here, debaters need a higher level of language ability. In ____ word, debating gives students a better understanding of Western culture and lets students practise their thought.
处的切线方程是 （ ）
