1. The following Halacha applies any time that we bentch, and we bring it here because we wash and bentch three times on Shabbos: HaRav Moshe Feinstein, Z’tl, in a Responsa (Igros Moshe, Orach Chayim IV: 41) writes that in order to bentch on bread one must eat a minimum shiur of a kezayis within a kedei achilas pras--and that shiur is less than three minutes. It appears from the Responsa that, b’dieved, one has up to 4.5 minutes within which a kezayis must be eaten, but one would clearly be better off according to Rav Moshe within the three minute span. The Mishne Berurah (Shulchan Aruch, Orach Chayim 167, seif katan 35) writes that, barring other circumstances, one should eat that minimum kezayis at the outset of the meal. We note that the shiur of kezayis consumption within a kedei achilas pras (so that a Bracha Achrona can be recited) actually applies to all foods at all times--so that, for instance, one must eat a kezayis of cake within the same three minute span in order to make an Al HaMichya. (Shulchan Aruch, Orach Chayim 210, Mishne Berurah seif katan 1). The shiur for drinks is different (ibid.).
2. When different types of toys are mixed together, one is not permitted to put each toy in its proper place (due to the prohibition of Borer). Rather, one should put them away in a mixed manner, and after Shabbos rearrange them in their proper order. [Children in Halacha by Rabbi Simcha Bunim Cohen, Shlita, p.141].
3. One does not violate the prohibition of Koseiv (writing) if he has letters or a design on the bottom of his shoe that makes an imprint on the ground, because if it is writing at all, the imprint does not last, it is done "kilachar yad"--in an unusual manner--and it is not something that the person in any event wants to happen. However, if one intentionally writes in the sand, or on a foggy window pane, or with crumbs on the table, he violates an Issur DeRabbanan of Koseiv. One should also not place magnetic letters next to each other to form a word on a board or on the refrigerator which will hold them together to form the word. [HaShabbos BeTifarta (Hebrew) by Rabbi Avrohom Adas, Shlita, Volume 2, pp. 389-427]
Important Numbers
