The courses of CET-4 and CET-6 in Du Wen Online School are quite good. I took his class when I was preparing for Band 4 last year. Du Wen Online School will launch a special first-aid information package for Band 4 and Band 6 before the exam. The data package contains a large number of exam questions, as well as a large number of English composition model essays and simulation questions, which can help students quickly measure their English level and facilitate students to choose suitable courses.