What means 上？ Recently i saw a phrase where a women said 你怎么做上饭了啊？ And i would like to know how often this happens and what it is used for.Please explain to me
Here, it suggests something has begun and continues to develop in its pace. It is prefered when talking about activities that requires quite some time, especially time for waiting. Apart from cooking, You can also use it in computer related context including 下载 (downloading), 编译 (compiling), 渲染 (rendering) etc.
Translation could be: Why have you already begun cooking the meal?
Note that 上 has many other usages, and it can suggest a mix of several meanings at the same time.
Here is an example: 等我回到家，家里人已经看上电视了。
Here, 上 still carries the sense that something has begun. However, because 上 also suggests "managed to do something", e.g. 赶上了火车 (managed to get on the train in time) or 没买上明天要用的书 (hasn't been able to buy the book needed tomorrow), this 电视 example also emphasized the fact that my family managed to watch the TV but I didn't.
A similar word would be 开. However, nuances exist.
For example, both 吃开了 and 吃上了 suggest that someone has begun eating the meal. However, the former emphasizes the lively scene that the meal has begun and people are eating with joy(?) while the latter would suggest the difficulty of getting to the meal. (e.g. in a foreign country and you could not find a restaurant or the person who usually cooks is absent) As for usage, 开 is a much more dialectal and colloquial term and is hardly followed by an object like 吃开饭了 (Personally I feel this ok but it is indeed very hardly seen or heard), while 上 is more widely used.
Pedroski's explanation is also possible. However, in such a case, the word 饭 will be phonetically emphasized so as to show the fact that one is cooking but not doing something else. The basic meaning of the word does not change: Such a blaming mood may naturally appear if something has already begun and could not stop easily.
The Chinese character "上" is used in different contexts in the Chinese language, highlighting the aspect of an action or event that has begun, and is proceeding, or has been completed.
For example, in the phrase "你怎么做上饭了啊", "上" communicates the idea that an action, in this case, cooking, has started already. Similarly, in "差点没'上上'上上海的车", the first "上" is a verb meaning to "board" or "catch", the second "上" indicates an action has started or been completed。
Furthermore, adding prefixes like "你怎么" or "你咋就" before these phrases can express a form of good-natured complaint, implying surprise or sarcasm based on the situation.
For example: 你怎么做上饭了？ (How did you start cooking already? I was just about to suggest going out to eat); 你怎么吃上饭了？ (How did you start eating already? You haven't swept the floor yet!); 你咋就看上电视了？ (How did you start watching TV already? You haven't cleaned up the table and dishes yet!).
Here, 上 = 起, which means to start/begin an act at the present time (now), and implies that the action is of something unexpected.
(我們)不是說好了晚上出去吃, 你怎么做(上/起)饭了啊？- Didn't we agree to go out to eat tonight, why do you (start to) cook now?
你不是戒了嗎, 怎麽又抽(上/起)菸了? - Didn't you quit smoking, why (start to) smoke again (now)?
不是該去上學了, 怎麽又玩(上起/)電子游戏了? - Shouldn't you be going to school, why (start to) play computer games now?