"There is no drink in your bag, Arwa."
Translation:لَيْسَ هُناك مَشْروب في شَنْطَتِك يا أَرْوى.
As you know, in Arabic, we use three letter roots, and insert them into various templates, to form words with various shades of meaning. Like prefixes and suffixes in European languages. And traditionally, we name those templates by applying them to the root f-3-l "to do." So I don't actually mean the actual word "maf3uul," but the template where you say "ma-" then put the first and second letters of the root, then say "uu," then put the final letter. Taking the root f-3-l ('to do'), and putting it in, you get maf3uul, literally "that which is done," or "effect" as you said. Take f-h-m ('to understand'), put it in, you get mafhuum ('that which is understood'), or "concept." Take the root j-n-n ('to be a genie'), put it in, majnuun ('he who is haunted by a genie'), or "mad person," and so on.
The term "binyan," בניין, is actually a Hebrew term that Westerners use when they talk about Semitic languages. While we Arabs also use that word to mean "construction/building" just like Jewish people do, when it comes to its grammatical meaning, we are more likely to call grammatical templates أوزان, or literally "weights," than بنايات, or "constructions." In Arabic, we say things like "The word maktuub is to the weight of maf3uul."