In my opinion, parents should strictly limit teenagers' screen time because spending too much time on screens can lead to negative effects. Firstly, teenagers may have little time left for homework as they often spend hours watching videos, using social media, or playing games. This can affect their academic performance. Secondly, too much screen time is harmful to their health. It can damage their eyesight, reduce sleep time, and even cause weight gain. Although some people argue that screen time can be educational, the quality of screen time is not always guaranteed. Therefore, it is important for parents to set clear rules to help teenagers use their time wisely and stay healthy.