Qur'anic Verse

During the revelation of the Verse of Purification, Imam Ali, Lady Fatima, Imam Hassan, and Imam Hussain (as) were present under the sheet with the Prophet (as). What could be the reason for Lady Zainab's absence at that time? Sayyed Mohammad Al-Musawi	Does Allah's statement in Ayat 66 of Surah Al-Anfal "الآن خفف الله عنكم و علم أن فيكم ضعفا" mean that Allah only knew at that moment that they were weak or if Allah had known it since the beginning of time, and what is the reason for this? Sayyed Mohammad Al-Musawi
Are there 14 places in the Quran where one has to perform prostration? And are they necessary to perform right at the time of reading the verses or can they be done later as well? Sayyed Mohammad Al-Musawi	What are the two verses of the Quran which end with the alphabet ش? Amina Inloes