"Lunch time is short."
I think it's because lunch time is not always short. For example: 「お腹が痛いよ」which means "My stomach doesn't feel well." It is not general but a temporary thing or something you just feel or discover at the moment. In most short sentence like this,「は」is for truth；「が」is for phenomenon. But in some cases like 「冬は寒いが、夏は暑いです」to compare two things (winter and summer), we put は between their (n.) and (adj.)
The distinction between は and が is not an easy topic, and can be the object of thesis in studying of japanese language.
In general manner, は is more the theme/topic of the sentence, meanwhile が is the subject of the sentence.
It can depend on what you want to underline or emphase, but fundamentally the scene described by the sentence is the same.
Some expressions have to be constructed with either は or が, and can not be changed. You'll have to learn them (for example "I'm hungry" mentionned in a previous reply)
In many cases, the theme and subject are interchangeable.
In many cases, the theme and subject are interchangeable.
彼が 古い（です）。 -> Litteral: He [subject] old. Can be translated to: * He is old.
彼は 古い（です）。 -> Litteral: He/Him [theme] old. Can almost be translated to: Regarding/As for him, he is old. Or As far as he is concerned, he is old.
If you prefer, these differences can a little bit be the same in English :
(What) a beautiful house. -> no verb (and so no subject), but the 'house' is the theme, the described thing.
The house is beautiful. -> a verb 'is' related to the subject 'house', which is also the theme.
It is a beautiful house. -> a verb 'is' related to the subject 'it', related to the theme 'house'.
Here is an example where it can be put as a topic marker. The translation I'll make can sound not very English, but you'll understand my point.
昨日友たちと話しました。 -> Simple sentence I would translate to: * I talked with my friends yesterday
昨日は友たちと話しました。 -> Here, "yesterday" is marked as the theme, then I would translate the sentence more like : Yesterday, I talked with my friends" Or Regarding/Concerning yesterday, I talked with my friends.
Both sentences mean the same thing, but not really. In the second example, "yesterday" is apart, and takes a more important part/value than in the first sentence where it is mixed within the sentence, and so appears as important as the fact the guys you were talking with are your friends.
You also could mark the giys you are talking to as the theme. And say something that could sound like Yoda or poetry in English : 友たちとは昨日話しました。 * "As for my friends, I talked yesterday with"... -> In this litteral form, you clearly insist on the guys you were talking with, and makes it a important piece of information. The fact is was yesterday seems less valuable.
が is the natural particle here. Did you read CH0063's explanation above?: https://forum.duolingo.com/comment/23344994?comment_id=26708119
The emphasis is on lunch break in a specific situation (lunch break at your specific work place, が), versus all lunch breaks at every place in the world (a truth about all lunch breaks in general, は). は can also be used for contrast (lunch break is short, but if you work the night shift, dinner break is long), but there's nothing in the English to imply that contrast, so が gives the most neutral sentence.
All of the above are correct. But I just try to categorize the sentences that are talked about because they are of different use cases.
The 5 categories of は vs が: https://forum.duolingo.com/comment/35559111
「お腹が痛いよ」=> Phenomenal sentence vs conclusive sentence. お腹が痛いよ talks about what is happening now, so it is a phenomenal sentence so が is used.
「冬は寒いが、夏は暑いです」 => Contrastive vs exclusive. It is doing contrast so は is used.
「昼ご飯の時間が短いです」 This one is ambiguous given no context. I would say it is phenomenal sentence vs conclusive sentence. If you talk about the lunch time that is happening now then it is が. If we are talking about other company's lunch time vs own company's then it would be "Contrastive vs exclusive."
I think both が and は can be a natural choice for this sentence.
I don't really think we're saying anything different. If you use it in a "contrastive vs exclusive" way, then you're adding nuance to the Japanese that is not present in the English. I'm not saying that は can't be used, but I strongly disagree with the OP's statement that は is more common, when が is the particle for making a neutral statement.
So, from what little I know and understand, pronunciations are hard for Kanji because they have Chinese 'On' and Japanese 'Kun' readings and variations within those readings that have to do with the context, the placement of the kanji in relation to other ones in the complex word, as well as the pronunciations of the Kanji around it.
Simply put, there isn't a great way to discern the differences quickly afaik and it's more rote memorization.
The の/no particle is used to signify possession, similar to the apostrophe-s ('s) in English (e.g. the cat's ears vs. 猫の耳・ねこのみみ・/neko no mimi/).
You will also see の/no translated as "of"; however, in such cases, the order of nouns is different, which can cause some confusion. With "of", the possessed object comes first: "<possessed thing> of <the owner>" (e.g. the ears of the cat). With の/no, it's the opposite order: "<the owner> no <possessed thing>" (e.g. 猫の耳・ねこのみみ・/neko no mimi/).
In this exercise, "lunch" is the owner of the "time". As such, you can think of the sentence as "lunch's time is short", "the time of lunch is short", or even "the time belonging to lunch is short". In English, we shorten "the time of lunch" to "lunchtime", which results in "lunchtime is short".
Let me know if that helps!
That's a fantastic way to explain it! I've been familiar with how No works with possession for a long time, but I was having a hard time thinking of it naturally in this application. Thinking of it as "lunch's time is short" makes it feel like a natural fit, and the logical choice when trying to form the sentence. I'm glad I looked at the comments in the one, this will make it much easier to make this type of sentence reflexive.
That would work in some contexts. If you work in an office that has 昼休み (hiruyasumi), which is the one hour of the day where everyone leaves to presumably eat lunch, it makes sense.
But if you're at a school, 給食 (kyuushoku) is lunch time and 昼休み (hiruyasumi) is recess/play time.
When you say ～の時, it's usually translated as "when ~". A common example of this grammar would be 子供の時 (kodomo no toki), which means "when I was a child". It seems like in your sentence you're saying "when it's lunch, it's short", so I think the nuance would be a little different.
I assume you're talking about this sentence: ちょっとの間いそがしいです。
I think you're trying to see a relationship between two completely different words.
間 (aida) means "a while", so ちょっとの間 (chotto no aida) is "for a little while". 時間 (jikan) means "time", so 昼ごはんの時間 (hirugohan no jikan) mean's "the time of lunch" a.k.a "lunch time". Even though they use the same kanji, both the Japanese and the English is different.