I can't send messages when imessage is closed. It always shows that imessage must be enabled to send this message. How can I send a message if I don't want to enable imessage?

I just figured it out myself, and the solution is very simple, that is, delete the short message record with this person in the message (I once sent an iMessage, and I can't send an ordinary message every time in the future), and slide to the left-delete. Then click on the pen and paper icon in the upper right corner again, write a new message, select the person to send, and then press the send button, green (indicating to send as an ordinary short message, blue indicating to send as an iMessage). The only drawback is that the historical record is gone. If you have a better idea, please tell me ~ ~