来尝试一种别样的通讯体验吧。Signal 不仅提供各种常见的功能，还尤为注重隐私安全。 When you've chosen to have to have admin approval just before persons can sign up for a call, you will see requests to hitch the decision which you can approve or decline. You may as well remove folks from phone calls and optionally block them from your contact https://www-signal.com/