"I eat fish."
At last I found this. But I didn't read all of them. Sorry.
The まして in はじめまして is actually a somewhat old way of speaking, which isn't commonly used nowadays, I believe. Essentially, it's the polite version of the て-form, which has a couple of grammatical functions.
One of these is to indicate a series of actions, which はじめまして kind of falls under, I think. As far as I know, はじめまして is actually a shortened version of the sentence 「はじめまして("to do for the first time")お目にかかれて("to be able to meet", lit. "to be able to set my eyes on")光栄("honor")です」 which is a very polite way to greet someone you meet for the first time (though it will sound very stiff and over the top in today's language).
I'm not sure what you mean by kudamashte... as far as I'm aware, that's not a correct conjugation. Perhaps, 「くださいましてありがとうございます」? It's a formal phrase for "thank you for doing that for (someone so lowly as) me"
Well, it also seems that they're different from what we commonly call the "subject" of an English sentence. In almost all of these examples, the unseen "I" (or "you" or "he" or "she") is what we would call the "subject" in English grammar, but it's the "topic" with regards to "は". Extra little layer of confusion there.
That's why I'm bothered with all the simple explanations people give on here, because you really can't expect Japanese to follow English language rules. And it doesn't help understand the way these particles work but instead just causes confusion.
Personally, this article here really helped me get a better grasp ond を and が http://learnjapaneseonline.info/2016/09/04/is-there-a-grammatical-subject-in-japanese/
I really don't think it's helpful because が doesn'talways work the way an english subject would which is really confusing in many instances if you strictly adhere to が = Subject.
To really make you grasp the concept of it I recommend everyone reading this article http://learnjapaneseonline.info/2016/09/04/is-there-a-grammatical-subject-in-japanese/
は marks the subject of the sentence and を marks the object. In this exercise, I am the subject so I write 「わたし」は, and the object that I'm eating is the fish, so I write 「さかな」を. It's very common in Japanese (as well as Korean) to indicate the subject and object in a sentence.
If you look at the sentence, you'll notice that it has no time tag to it (meaning that it's just saying "in general, I..."). That being said, if you use は, it makes it general where you say, "As for fish, (I) don't eat (in general/ever)." If you were using を, it wouldn't have a direct time tag on it, but it would be more of an implied 'this will happen in just a second/in the near future.' 私は: ステーキはたべます。I eat steak (from time to time, in general, etc.) ステーキをたべます。I will eat steak (in a second, a few minutes, etc.)
Research particles online.
Watashi along with similar words, means all of those things wheb paired with the right particles. は and が are good examples of such particles. は and が are very similar but both have different uses. は is often referred to as the topic marker particle, which means that when comes after a noun it sets a new topic for the conversation. が however is more often used in connection to question with specific answers. In a way you could say that が translates to "... is the one".
If you want to know more about this I suggest you google Tae Kim and find his blog post on this, as he does a good job explaining it.
I don't know what I did wrong. I wrote さかな (sakana, fish) を (wo, object marker) 食べ (tabe, eat), but it wasn't accepted. My understanding is that my sentence would have been correct in the context of a conversation about different foods that I eat and that 私 (watashi, I) さかな (sakana) を (wo, object marker) 食べ (tabe, eat) ます (masu, I think it makes it more polite) would be correct when I (the subject and topic) was not already the topic, like for example if we were talking about what YOU like to eat and when you mention that you do not eat fish, I politely point out that I do.
Can someone please explain?
Just adding to what flypirat said, you're right in that ます does show politeness, but not as simply as just being there.
The root word for the verb "to eat" is 食べる. You can use this as a verb in plain/casual speech. When you want to show politeness, you should conjugate it into ます-form. Depending on the class of verb, there are a couple of different rules for doing this, but in the case of 食べる, it's simply done by replacing る with ます. Like flypirat pointed out, you need to put the ます back on to complete the verb conjugation.
So in essence, you show politeness by using different forms of the verb, rather than the mere presence or absence of ます.
Tbh it's very unfortunate to see so so mucb discussion/guesswork being done here. This Duo course is not suitable for learning grammar as it explains nothing.
Please people, refer to books/other apps and websites (like JA Sensei or Tae Kims Guide) to understand basic particle usage and verb conjugation :/
By including I you are emphasizing that you are the one that does not eat fish. For example, youre in a large group of people and youre all asked if you eat fish. Not including I would be like saying no one in the group eats fish, but that might not be true if you dont know for sure.
を doesn't indicate "I" in any sentence; it's always the "object particle" and indicates what the verb acts on.
In previous exercises, 私は (which actually indicates that "I" is the topic of the sentence) was left out because, as the others have commented, it can be left out, and often is, if it is obvious you are talking about yourself.
This is one of the things i dont like about the app. How was someone supposed to know that that was the kanji for fish. It was never introduced before.
And reading all the comments shows that you already have to have some background in japanese already to understand what they are doing. Especially all the grammatical particles.
I really recommend you reading this article http://learnjapaneseonline.info/2016/09/04/is-there-a-grammatical-subject-in-japanese/
It helped me get a better grasp on が and を
@sora_Japan also posted a very helpful cheat sheet from Tofugu in an earlier comment. I would recommend reading through the other comments on this discussion page to help you get a feel for it too.
But, I wouldn't worry too much about it at this stage. Using particles takes some time and exposure to get used to, and time spent analyzing why a specific particle was used can be better utilized by getting more exposure to the different ways particles can be used. You'll just get a feel for what's right eventually.
The を is there to mark the object of the sentence. It identifies a noun or a noun phrase as "the thing the verb acts on".
Like all particles in Japanese, it is a "postposition", rather than the "prepositions" we are used to in English. So in this sentence, the verb ("eat", 食べます) acts on/gets applied to the noun that came before を, which is 魚 ("fish").