Language teaching aims at the integrated development of the four skills to ensure that students can communicate effectively in various situations. Concerning the integration of skills in the English classroom, analyze the following statements:

I.Listening activities should include authentic materials to expose students to different accents and natural speech patterns found in global communications.
II.Writing is a productive skill that involves a process of drafting, revising, and editing to convey a message clearly and appropriately to a specific audience.
III.In contexts where large classes and limited instructional time are present, speaking activities may be postponed and substituted predominantly by controlled written drills, under the assumption that oral proficiency will develop spontaneously from exposure to grammar and reading tasks alone.

Which statements are correct?