grammar - What is the noun in the second sentence?

This is a continuation of the question at A significant amount of zombies were detected in your city which raised further questions in my attempted answer.

There were purchases. A significant number of them was/were detected.

From [Oxford Dictionaries][1]:

Although the expression ‘a number’ is strictly singular, the phrase ‘a number of’' is used with plural nouns (as what grammarians call a determiner (or determiner)). The verb should therefore be plural:

A number of people are waiting for the bus.

This is not the case with ‘the number’, which is still singular:

The number of people here has increased since this morning.

It can therefore be argued that "them" refers to "purchases". Is "them", "purchases" or "a number" the noun in the second sentence, and why?

Answer

'A significant number' is a stand-in for what can only be imagined as a relatively large number. More importantly, that number of significant size would merit pluralization.

"1 was detected"

"2 were detected"

"A significant number were detected"

"A number [of something] were detected"

As the only number that leads to the singular case is 1, pluralization is the natural choice for unspecified quantities.

To answer your question, the noun is 'number.' The definition of number, per Google:

1.
an arithmetical value, expressed by a word, symbol, or figure, representing a particular quantity and used in counting and making calculations.

2.
a quantity or amount.

Considering the second meaning of 'number,' the pluralization is much more rational.

EDIT (after comment by Edwin below)

Plural noun usage is explained nicely here.

Relevant quotation:

Note that "the number" is a singular collective noun. "The number of applicants is steadily increasing." "A number," on the other hand, is a plural form: "There are several students in the lobby. A number are here to see the president."

Simple Past or Past Perfect

If I went to a place last night where I needed to show an id, but I forgot to have it on me. So if in the morning I was speaking to a friend(reporting on what happened), which one of the following would be correct:

I had heard that you needed an ID, but I didn't know if it was absolutely necessary

I had heard that you need an ID, but I didn't know if it was absolutely necessary.

I heard that you need an ID, but I didn't know if it was absolutely necessary.

The first one seems correct to me, but I might be wrong. Ideas?

And which one of the following should I say in the context above:

Reporting on what had happened

Reporting on what has happened

Reporting on what happened

Answer

I had heard that you needed an ID, but I didn't know if it was absolutely necessary.

This sentence is correct. It implies that you knew about the necessity of carrying an ID before the events of last night.

I had heard that you need an ID, but I didn't know if it was absolutely necessary.

This is also correct, although some people might say that the use of Present Simple with need doesn't agree with the past perspective. I believe, however, you can use it because in this place the ID is a norm and it is still valid.

I heard that you need an ID, but I didn't know if it was absolutely necessary.

This is correct but not very clear. I heard doesn't show that you knew about the ID beforehand. I prefer the previous two examples.

You are reporting what happened since you have already mentioned that these events took place last night.

pronoun usage with a preceeding a

What pronouns would you use in the following sentence

John and Lou recognized a bear cub. Replacing the proper nouns with a pronoun and then replace bear cub with a pronoun.

numbers - Do we have to use ordinals with largest/smallest?

In every-day language, I would say, "Give me the fifth largest pumpkin you have"; that is I would use the ordinal.

However, this feels clunky in mathematical texts, especially when reading out loud: "select the k-th largest element" or, even worse, "the k plus first/oneth largest element".

Is it fair to say/write "the k-largest element"? It seems to me that the "aspect of ordinality" is sufficiently expressed by the -st suffix in larger (or smallest, heaviest, ...), that is the superlative.

grammaticality - "A" or "an" in front of a number that can be read in two ways

Consider the following sentence.

We are selling ___ 1,800 sq ft office.

I would write an, because I say eighteen hundred.
But someone else would say a, because they say one thousand eight hundred.

For 2,000 it's easier, because it's always two thousand.

For 2,100 it can again be twenty one hundred, or two thousand one hundred.

So what is grammatically correct, what do I write so that I don't confuse my readers?

grammar - Is the use of whom appropriate in the phrase "You are with whom your mind is."?

And why?

I always see whom used in questions. This is not a question, is a statement. Whom sounds correct to me, but I'm not sure if it is and why.

The "rules" I've seen around are all for questions, not for statements. In this case, "whom" seems the object to whom (hehe) the action of "being with" is performed. Is this correct?

Answer

The distinction as I understand it after reading the comments is essentially about the distinction between the possible sentences:

You are with whoever your mind is with.

and

You are with whomever your mind is with.

My answer is that the latter is correct and the former is acceptable in many variants of modern English.

Reasoning

We say, 'You are with him.'

We do not say, "You are with he."

The above is almost universally true, regardless of grammatical terminology.

We can say, 'You are with whom?'

In many varieties of English we can say, 'You are with who?'

We merely have to extend this series in order to arrive at the two sentences I started with.

grammar - word order in superlatives: "She booked the earliest flight to London she could." or "She booked the earliest flight she could to London."?

What is the correct (Ooops, I'm afraid it's me again! rule-o-cratic French speaker), preferred, then, word order in a superlative?

"She booked the earliest flight she could back to London."

or

"She booked the earliest flight back to London she could."

Or neither, the sentence sounding awkward anyway… How would you put it then?

Answer

As to rules, several have already applied in both of these sentences

• She booked the earliest flight she could back to London.


• She booked the earliest flight back to London she could.

To start with, let's put back most of the deleted words

• She booked the earliest flight that she could book that goes back to London.


• She booked the earliest flight that goes back to London that she could book.

Note that there are two relative clauses modifying flight

• the earliest flight that she could book


• the flight that goes back to London

They are both a result of the superlative construction, listing its two boundary conditions:

1. she was able to book the flight


2. the flight goes to London

Given these conditions, the superlative earliest refers solely to time of departure.

The order in which several relative clauses that modify the same antecedent may appear
in a sentence is open; this is a matter for the speaker's judgement, as usual.