Learn Arabic (Modern Standard): كان عند المتسلل المحترف جواز مزور واسم مستعار. - The professional infiltrator had a forged passport and a false name.

In Arabic, there is no verb for "to have." To express possession, you use a preposition like عند (with/at). To put this in the past tense ("had"), you simply add the past tense verb كان (was) before it. So, كان عند المتسلل literally means "there was with the infiltrator."

Notice how almost all the descriptive words in this sentence start with the letter مـ (miem). Why is that?

Words like المتسلل, المحترف, مزور, and مستعار are all participles from derived verb forms (Forms II through X). In Arabic, both active participles (the "doer") and passive participles (the "receiver" of the action) for these longer verbs always start with the prefix مُـ (mu-).

How can I tell that المتسلل (the infiltrator) and المحترف (the professional) are active participles?

For derived verbs starting with مُـ, look at the short vowel on the second-to-last letter. If it is a kasra (an "i" sound), it is an active participle. Both المتسلِّل (al-mutasallil) and المحترِف (al-muḥtarif) have that "i" sound before the final letter, showing they are the people doing the action.

What makes مزور (forged) a passive participle?

Instead of a kasra, passive participles have a fatha (an "a" sound) on the second-to-last letter. مزوَّر (muzawwar) has this "a" sound, indicating it is the receiver of the action: the passport is the thing that was forged by someone else.