The guidance in the text is, in my view, oversimplified to the point of being incorrect.
Many idioms and fixed phrases are typically used in informal situations. For example "take a load off your feet" (or often just "take a load off") is quite informal. It should not be used in formal situations.
But idioms such as "Good things come ...
To be short of an amount of something is to have less than that amount. E.g. if I am ten cents short of the dollar I need for something, I have 90 cents.
To say that someone is [one thing] or [a few things] short of [a complete set or collection of things] is to say that that person is mad or stupid - lacking a complete set of mental faculties. A slab is a ...
It is indeed an idiom. From The Free Dictionary:
put someone up
Farlex. 4: To provide one with overnight accommodation, especially temporarily. A noun or pronoun can be used between "put" and "up."
We're putting up Jen's brother for a couple of weeks while he looks for a new apartment.
The airline offered to put me up at a hotel for the ...
In the UK, the most common term would be "private tutor". They might also be called a "home tutor" or possibly "personal tutor", but the teaching could be in any setting, not just a personal home. Being taught individually by a professional but not in a school setting is nearly always referred to as "private tuition".
In computer programming, "the metal" is slang for the actual computer hardware itself. For a program to run, there are several layers of computer languages that run to eventually make the computer perform the correct actions. For example, "machine language" is the code that directly tells the computer what to do, and it's all "zeros&...
Your book is giving a completely incorrect explanation. It equates "fixed expression" to "idiom," and then suggests that idioms are "often" informal. This is all wrong.
A fixed expression doesn't have to be an idiom. For example, "due diligence" is a fixed expression in English that recently has seen a lot of over-use. ...
Open source means that the source code for the software is openly available: it isn't proprietary (someone's private property). "Down to the metal" means that all levels of the software are open source, from the user interface down to the computer hardware (the metal) that the software runs on.
It's likely an exaggeration, though.
You could gloss it by "One thing you should know...", but "however..." might do as well.
The example sentences you quote both suggest a contrasting context. Mind you, the dictionary may not have room to include complete context.
I can't find the sources online, so here's some conjured context:
A. Do you have positive memories of your ...
There is nothing special about this idiom. Whether you use a or the follows the normal rules, namely, whether you are talking about a generalized chance or a specific chance.
Consider the unmodified noun "a chance." We use the definite or indefinite article depending on context:
She didn't have a chance.
He had a slight chance.
There was a chance.
It seems we can, though I've only ever heard the ghost.
In "He saw a ghost. It was the ghost of a child" we switch from the indefinite to the definite article, believing - as I think we do - that we are entitled to just one ghost each. We certainly wouldn't speak of 'a ghost of the child.'
On the other hand, speaking metaphorically we might say &...
(a) is not wrong, but we don't normally speak of 'holding one's breath' for an event that won't happen for a month - in fact we say 'Don't hold your breath' to warn someone that they may have a long wait. See Meaning of "but don’t hold your breath"?
I would expect (c) to imply that the speech would be made quite soon; perhaps within hours, though ...
It is not explict, but pot probably refers to "pot of tea", and "put on a fresh pot" is to make a new pot of tea to share.
Tea, in Britain in particular, is a popular drink to have while having a chat.
This is a metaphor. The key words are:
An elevated place or structure before which religious ceremonies may be enacted or upon which sacrifices may be offered.
For slaughter, see sacrifice:
a. The act of offering something to a deity in propitiation or homage, especially the ritual slaughter of an animal or a person.
The context you've quoted it in doesn't seem to make sense, but in English all of these 'you're one xyz short of a....' are essentially all the same. They usually mean that someone is crazy, or that something doesn't work properly.
"He gets woken" does not mean "he wakes up" but rather "someone awakens him". "He gets awake" sounds wrong to a native speaker. It might possibly mean "He becomes awake" or "he wakes up" as in
After the light shies on his face, he gets awake gradually.
but it is still a strained and unusual ...
The source of the quote is a Chinese official who is not a native English speaker, I would imagine. It is also possible that the official spoke in Chinese and the statement was translated by the news source.
The phrase is not one that I recognize but yes, the meaning is clear: to do something that will backfire and cause you harm. In this case the possessive ...
A person's "word" can mean more than just what they say. It can carry the meaning of their reputation for being truthful. A similar expression "my word is my bond" shows that what a person says can be seen as a binding agreement, and something of value, like a bond.
Saying something is "as good as" something else draws a ...
The 's marker does not always indicate possession.
My favorite song means the song that I like best.
Brooke's favorite song means the song that Brooke likes best. And it means only that. It indicates nothing about the person who wrote or recorded the song, who owns the copyright, or anything like that.
Collocation is a reasonable way to describe this pattern....