Hello shalala,
I have your answer in my mind because I have learnt this in the university this year, by the way this is my first year at the university.
Let's start
When you pronounce a verb close your both ears and listen to the last sound, when you find some kind of vibration regardless the degree of vibration then you must pronounce the end of that verb like this /d/, for example the sound /eɪ/ in the verb play you feel some kind of vibration and those are the sounds that must be pronounced /d/ in the past form of some verbs: /ð b g z ʒ dʒ l r w j m n ŋ/.
whenever you find no vibration in the last sound of a verb then you must pronounce the end of the verb like this /t/, to illustrate this we take the verb finish which ends with the sound /ʃ/ there is no vibration in this sound so we pronounce the end of this verb like this /t/ and those are the sounds that must be pronounced /t/ in the past form of some verbs: /θ p k s ʃ tʃ/.
finally there is one exception with the sounds /t/ like in want and /d/ like in demand. both of them must be pronounced like this /ɪd/.
I think that's all I can say for you Shalala and I hope that my explanations were helpful for you and for other members in this forum.
see you ;-) :lol: