If a woman’s period ends after the time for `Isha' has begun, then she must pray `Isha' because the time for it has come. At the same time, she must also pray Maghrib because it is a prayer that can be put together with `Isha' when there is a valid reason for doing so. If the period ends after the time for `Asr has begun, she should pray Dhuhr and `Asr. If she becomes pure after Fajr, or after Dhuhr, or after Maghrib, she only has to offer one prayer, which is the prayer at the time of which her period ended (Fajr or Dhuhr or Maghrib).

If the twilight disappears long enough before dawn that they can pray `Isha’, then they have to wait until it disappears. Otherwise if it is too hard for them to wait, in that case it is permissible for them to put `Isha’ together with Maghrib at the time of the earlier prayer, so as to avoid hardship and difficulty.

The true time of Fajr refers to the appearance of the second dawn according to consensus. That is indicated by the reports of the times of prayer. The second dawn is the white line that appears along the horizon; it is called the true dawn (Al-Fajr As-Sadiq).

It is not permissible to delay the prayer beyond its time because of work as work is not an excuse for delaying prayer. Zuhr and ‘Asr and Maghrib and ‘Isha prayers are the ones that can be combined (in some cases). But you cannot join `Asr and Maghrib. So you must organize your time at work in a way that will not interfere with your performing the prayers on time.