Good "cassette tape marking" can help revise students' compositions, because they can show to the student the "goal" of revision. Good "cassette tape commentary" do not comment on minor linguistic errors such as wrong words or wrong sentence structure. Instead, such comments focus on macro linguistic errors such as theme and the overall structure of the composition, so that the student can revise his writing in these directions. As a result, the student's writing can have a clearer theme and a more logical structure so that the whole piece can be improved. Another reason "cassette tape commentary" can help improve students' compositions is that it exemplifies the relationship between the writer and the reader so that the student can have a better grasp of the reader's expectation. The present study uses Form 1 Chinese Mainland students as subjects. One-way ANCOVA results indicated that "cassette tape marking" can significantly raise students' writing performance.