Read the【Case Reflection】in this section and think about the questions:

Mr L pays a lot of attention to English writing. He gives writing assignments to his students every week, and sometimes a writing task after a class discussion. According to him, continuous writing practice is the best way for students to improve their writing skills. He corrects each and every mistake in his students' essays and asks them to rewrite them. However, his students continue to make many mistakes in their essays and the work they hand in is not satisfactory. What do you think are the main problems with Mr L's teaching?