Hi, First the topic you are discussing here is considered advanced for beginners in Arabic, so it will prove some difficulty but it is not impossible. My greetings for trying to master this topic early when learning Arabic, but do not be intimidated if you can not master it soon. It will take some time. Second, you have to know that the maximum number of letters in a verb is 6 letters (excluding the subject indicators and gender and plural indicators) e.g.: يَفْعَل consists of 3 letters of the verb plus a letter to indicate that the subject is "He" in the present tense. تَسْتَفْعِلِي (tastafe'ly) consists of six letters (the main verb is استفعل) the first letter is ت to indicate "You" and the ي to indicate a feminine you. The original main verbs are either 3 letters long or 4 letters long. This type of verbs are called مجرد. Sometimes we can add one or more letters to create a new meaning from the main verb, e.g. خرج is to go out ... استخرج is to get something out of an archive or minerals out of earth etc. In this case the main verb was 3 letters and we add another 3 letters to form a new verb and that new one is called مزيد. So verbs with main 3 letters can be مزيدة by 1,2 or 3 letters max, while verbs with main 4 letters can be مزيدة by 1 or 2 letters only. In the case of the example you mentioned, the root verb is ذَهَبَ a 3 letter verb in the past tense, its present is يَذْهَب . Its وزن is فَعَلَ >> يَفْعَل . The verb you mentioned is يُذهِبُ is a 4 letter verb in the present tense. How we know that? By using the وزن: If a 3 letter verb is increased by 1 letter, then it may have one وزن of three types: - اَفْعَل: (Afa'l) that is the one you are asking for .. Here we add an أ to the main three letters so we say أذهَبَ in the past and to get the present form the وزن is اَفْعَلَ >> يُفْعِلُ ... so we get اَذهَبَ >> يُذهِبُ (compare this with the main verb with 3 letters only above)

القاعدة العامة أن الأفعال على وزن "فَعَلَ" تُصاغُ كما يلي: فَــــــــعَـــــــــــــل -> يَـــــــــــــــــــــفْــــــعَـــــــــــلُ -> افْــــــــــــــــــعَلْ مثل : قَعَدَ يَقْعُدُ اقْعَدْ و جَلَسَ يَجْلِسُ اجْلِسْ Hence and in the most times, verbs like "فعل" are written as previously.

The past is ذَهَبَ not أذهَبَ