yeah, "got a sec[ond]?" sounds good.
But to me "hold up a sec" kind of feels like the other person is in a rush to leave/is leaving and you have stopped them to say something.
The kind of phrase you are describing will only really be necessary to say, in casual conversation, if you are making a request or want to confess some problem. If you just have a normal question, you probably won't bother prefacing it with anything. And at times when you are making a request, even in casual speech, people tend to speak a little more politely than normal.
Perhaps "you got a moment?" or "you got a sec?" would be slightly more informal. However, if we were friends and you said "Do you have a moment?", I wouldn't think it unnatural. I would just immediately think some thing is wrong or you're about to make a decent request. "You got a sec"--I wouldn't anticipate something as serious following that phrase...
ETA: What does 私は中国の旗を求める場合 mean? Or to be more precise, what did you intend it to mean?
Sadly Arabic is not english...
Perhaps "you got a moment?" or "you got a sec?" would be slightly more informal. However, if we were friends and you said "Do you have a moment?", I wouldn't think it unnatural. I would just immediately think some thing is wrong or you're about to make a decent request. "You got a sec"--I wouldn't anticipate something as serious following that phrase...
Ah, I couldn't even see it, I thought that was some kanji for city! Yes, that is Ji/Chi, meaning for earth/ground, and owner...I get it! Chishu? Or something.
--e
Jinushi it is, now that I see it.
Lemme see if I can get your signature thing..
文字化けを避ける！
First one is writing, second one is character, third one is changing, next one is hiragana ke, then something that looks like (w)o, something else, ke ru.
Pretty good -- it's mojibake (w)o sakeru. It's the Japanese version of what's to the left of it in English (at least it hasn't been corrected since I put it up there three or four years ago). If you don't know what the word mojibake means yet, it's just because you didn't know that was the name for it. It's what you see when Japanese/Chinese/Korean/Thai, etc. doesn't display properly on your computer screen.
Well, generally 文 is bun, as in 文章 (bunshô -- sentence; writing), 文明 (bunmei -- civilization), 論文 (ronbun -- thesis), and 文化 (bunka -- culture), but is sometimes read mon, as in 文句 (monku -- phrase; complaint) and 文部（科学）省 (monbu(kagaku)shô -- Ministry of Education, Culture, Sports, Science and Technology), but in the case of 文字 it gets a special reading, and the word is moji (character, letter, etc.).
化 has an on-yomi of ka and kun-yomi of bake(ru). In this case, as you can see there's the け there, indicating kun-yomi. By the way, "chemistry" is 化学 (kagaku, although I think there was a movement to call it bakegaku due to "science" (科学) also being kagaku).
Err, maybe a moderator could split this discussion into its own thread and move it to Learning Japanese? I'd hate to keep hijacking grapefruit's thread, and this is pretty off-topic.