المضارع المرفوع أو المنصوب؟

I am sitting in on Rida’s morning class. This means I will not have my homework done for my own class with him this afternoon. I am reading an article about the relationship between Obama’s election and the Middle East and North Africa. Finding out exactly what the author thinks will just have to wait ‘til this evening.
At this very moment, the students are changing sentence from active to passive. In rather advanced sentence, they have just overcome an issue of changing long vowels in the verb beautifully, but missed a point of basic grammar when putting the sentence together. Rida praised the success of the passive, then paused opened palms to the class and said: I have a personal question: why have you put a fatha on the present tense verb? When do we put a fatha on present tense verbs???” Can any of you, dear students (above first year), recall this small, but important point?