Hi, Nice question, Let's consider verbs in English, you know some verbs needs proposition and some not for example go + to insist + on and some other verb do not need proposition like help + --- + somebody but in Persian the verbs that has propositions are different for example in Persian help is always used with "be" that is why some Persian speakers who have just started learning English might say " help to somebody" because they translate word by word so the answer is easy, you should take a look at your Dictionary to see each Persian verb need what proposition in your examples: 1-Ehtiaj dashtan + be (the verb Ehtiaj dashtan should be accompanied by 'be' that means 'to' but in in English we do not say need + to we just say need + - + something) 2 Residan + be ( in Persian residan should be accompanied by 'be' which means 'to' but in English we do not say reach +to we just say reach) hope you got the point have fun

"be" in many cases means "to" in English, but here they are expressions: 1- be chizi ehtiaj dashtan, e.g: (be pool ehtiaj dashtan: needing money) 2- be chizi residan (be otoboos residan: catching the bus at the nick of time) so, just learn them in an idiom, not as separate words. Movafagh Bashid;)

A class of transitive verbs require the object to be marked with a preposition, i.e. «be / به» in your sample sentences. You need to learn these verbs and the associated prepositions through practice.

The best comment I can offer to you is to put all those applications into the garbage. This parrot like talking method will not work. In short answer to your question: Be is an article in Farsi. Articles do not have any meaning by themselves. So you understand an article WITH the words before OR after it.