As an AI language model, I don't have access to real-time information or the ability to browse the internet. Therefore, I cannot provide you with the specific dates for the previous half-year's CET-4 and CET-6 English exams. However, I can certainly help you with some tips and guidance for your exam preparation.

Preparing for English exams requires consistent effort and effective strategies. Here are a few suggestions to help you make the most of your study time:
1. Set clear goals: Determine what you want to achieve in the exam and set realistic goals accordingly. Having a clear target will help you stay focused and motivated throughout your preparation.
2. Create a study plan: Divide your study time into manageable segments and create a study plan. Allocate specific time each day for different skills such as reading, writing, listening, and speaking. This will ensure that you cover all aspects of the exam and make steady progress.
3. Practice regularly: Consistent practice is crucial for improving your English skills. Utilize various resources such as textbooks, online materials, sample papers, and past exams to practice different question types and familiarize yourself with the exam format.
4. Enhance vocabulary and grammar: Improve your vocabulary by learning new words, their meanings, and usage. Also, focus on strengthening your understanding of grammar rules and sentence structure. Regular practice exercises and revisiting grammar concepts will help you solidify your knowledge.
5. Work on reading comprehension skills: The reading section often proves challenging for many test-takers. Practice reading different types of texts, such as articles, essays, and news reports, and work on improving your reading speed and comprehension. Pay attention to the main ideas, supporting details, and overall organization of the passages.
6. Develop listening skills: Listening comprehension is another crucial component of the English exams. Listen to a variety of audio materials, such as podcasts, news broadcasts, and TED Talks, to improve your listening skills. Take notes while listening and practice summarizing the main points.
7. Practice writing essays: Writing is an essential skill that requires practice and feedback. Write regularly on a variety of topics and seek feedback from teachers or native English speakers. Focus on structuring your essays clearly, supporting your arguments with evidence, and improving your vocabulary and grammar usage.

Remember, consistency and perseverance are key to success in any examination. Alongside your exam preparation, try to surround yourself with English as much as possible by watching English movies, reading English books, and engaging in conversations with English speakers.
Good luck with your exam preparation! With dedication and effective study strategies, you can achieve your desired results.
