Idioms are not all the same. As you've already found out idioms can function in all part of a speech (verb, adj, adv, relative clause, and so on)
In layman's terms, idioms are "common expressions" that can act as many word types and in most case, replacing a whole clause. You don't need to know any idioms to speak fluent Chinese, but you do need to ...
I think translation gives the clue.
那个人看来有点不三不四 -> That person looks like kind of 不三不四 -> adjective
我集市看到人山人海 -> I saw 人山人海 at the event -> noun
我开门见山就跟你说 -> I 开门见山ly say that to you -> adv; I 开门见山 and say that to you -> verb
你不要画蛇添足 -> You don't 画蛇添足 -> verb
車水馬龍 - prosperous and bustling [street|city|or...].
熟能生巧 - practice makes perfect.
突飛猛進 - make astounding advances.
一日千里 - similar to 突飛猛進.
刮目相看 - to view someone in a new ...
The function of 成语, or in this case, also 谚语 and 歇后语 is to express your idea "right on the target" economically and vividly. it is the concentration of a usually long story. Don't worry, if you fully understand them, you can use them any way you prefer as not to worry whether correct or not in grammar. People really get you. Be brave, use them ...
From syntax point of view, how do you know when the chengyu can be adverb or adjective or some thing else?
For starters, even individual words in Mandarin often can't be confined to a single part of speech. Take for instance the word 教. This word can be considered both a verb and a noun (the action "to teach" and the noun "teachings" ...
Here is an excerpt from the Wikipedia page for Chengyu:
As such, chéngyǔ are fossilized expressions that use the vocabulary and follow the syntactic rules of Literary Chinese. Consequently, they convey information more compactly than normal vernacular speech or writing. They may contain subject and predicate and act as an independent clause (or even twin ...
In my (long) studies I've never come across a formal definition of "definiteness/indefiniteness" specifically used to describe a grammar rule of Mandarin.
However the phenomenon you are talking about happens in many languages, and can be explained as stressing a certain element of a sentence by means of syntax (i.e. word order).
By rearranging the ...
You can find the answer in 百度百科 using the key word 语气词 in Baidu search. Here is the quote relevant to your question:
It has a table listed all the usages of those 语气词. I can't copy the table from my mobile device. But it has this example 我不会忘记你们的。to ...
The thing is, Chinese and English are so different that you would rarely see a sentence that can be translated word-by-word and in the original order, without sounding unnatural.
For example, Wiktionary defines 什么 as "what". But can we translate 你在做什么? (what are you doing?) without rearranging elements in the sentence? No, usually we can't. Does ...
As a Mandarin/Cantonese bilingual speaker, I would say don't worry about this line in the video, because I've never seen a sentence goes:
Noun1 莫过于 Noun2
instead, there is usually a 'most' ‘最’：
Most adj. something 莫过于 Noun2
Literally translated (to maintain the word order) as,
Greatest pain, (can) not ...
However, there are times we have to go do something that we hate...
The 去 go here functions in contrast to "hate" in the second part of the sentence.
It shows how much you hate to do it, but also need to do it. So you "go do it" anyway.
In your example,
with 去, it adds a bit emotion here. It sounds like that doing those things is extra miles. Without it, it doesn't have that connotation.
This dictionary definition addresses the use of 去.
（用在另一动词前， 表示要做某事）(preceding another verb, denoting will do):
Please go and ask.
We'll find a way out ourselves.
去 means 'go'. It can function as a verb particle that denotes the initiation of a verb. Similar to 'go' in 'go kill people' in English
我當教師 = I being a teacher
我去當教師 = I go and (begin to) be a teacher
因窮而犯法 = break the law because you are poor
因窮而去犯法 = go and (start to) break the law because you are poor
很多时候，我们不得不做一些自己不愿意做 = We often do ...