Busy: Students may be busy for various reasons, such as study and work, which makes it impossible to reply to information in time.
No: My brother may not have seen your news or missed the time to reply.
Don't know how to reply: Students may not know how to reply, especially when faced with some complicated or sensitive questions.
Not interested: A junior may not be interested in the topic or content, or it may not conform to his values and hobbies.
Network problem: My younger brother may have encountered network problems, resulting in the inability to use mobile phones or computers and other equipment normally.
If the younger brother doesn't respond, he can consider adjusting his expression and tone appropriately to increase the interactivity and interest of communication, and at the same time, he needs to respect the privacy and choice of the other party. If you don't get a response for a long time, you can consider contacting your schoolmate through other channels or seeking help through other means.