Use of قَدْ

The harf (حَرْفٌ) قَدْ is only used with فَعْلٌ.

When used with past-tense (اَلْفِعْلُ الْمَاضِيُّ), قَدْ is used to emphasize and imply certainty of the action, and may also include a meaning ‘already’. for example: قَدْ كَتَبَ means ”He already wrote” or ”He definitely wrote”.

When used with present-tense (اَلْفِعْلُ الْمُضَارِعُ), قَدْ can be used to imply certainty, or it may also give a meaning of ‘might’. The meaning depends on the context. for example: قَدْ يَعْلَمُ means ”He might Know” or ”He certainly knows” depending on the context.

Example:

قَدْ نَرَىٰ تَقَلُّبَ وَجْهِكَ فِى ٱلسَّمَآءِ ۖ فَلَنُوَلِّيَنَّكَ قِبْلَةً تَرْضَىٰهَا ۚ فَوَلِّ وَجْهَكَ شَطْرَ ٱلْمَسْجِدِ ٱلْحَرَامِ
We have certainly seen the turning of your face, [O Prophet], towards the heaven and we will surely rurn you to a qibla with which you are pleased.

…. [2:144]