Is one allowed to drink the juices which oozed out during eating; grapefruit issues.
ודבר דבר (Dabair Davar): Mentioning Something That Somebody Will Do After Shabbos When It's Not Allowed to Be Done on Shabbos Itself;
understanding the concept of מטה של פרקים (a bed used to travel that had to be put together and taken apart);
Interesting question in reference to texting, emails or phone call.