punctuation - Use of dash in a sentence

Is the dash an acceptable punctuation in this sentence?

Dances, parties, luncheons -- all these should be part of your senior year.

British English form of the word playoff

I've recently been across quite a few British sport(s) websites and Wikipedia articles and kept finding the wording "play off" show up to discuss the battle between two teams after the regular season.

In American English, I tend to think it's quite ingrained to use playoff, and that play-off is a rarer backup.

But seemed that play-off and even play off both come up more regularly in relation to British events... with play off even showing on some major sites (in the header of a Wembley Stadium Article, in a BBC Facebook post).

Google (searched from the US) shows
487,000 results for "NFL playoff" vs 17,100 for "NFL play off" compared to
62,900 for "League one playoff" vs 214,000 for "League one play off"
(The complexities of the plural form seems to further muddle things, as playoffs is a common term in the US, but perhaps not so much in the UK?). Also, Google lumps play-off and play off together under either search, and I can't find a way to overcome this?]

A quintessential comparison of the imbalance seems to be in
https://en.wikipedia.org/wiki/National_Football_League_playoffs vs
https://en.wikipedia.org/wiki/Football_League_One_play-offs.
Even though it's just Wikipedia, it seems to follow the larger scope?

Looked into dictionaries for more info... M-W indeed found play-off, with playoff only in the unabridged dictionary... and Oxford American redirected to playoff in the American English dictionary... but was surprised to see dictionary.com favors play-off over playoff. Seems US sport league websites and even the AP style guide for the World Series use playoff without discussion. But each just seems to list one form, without mention of regional usage. Is there any site that hammers it down to that?

Alternatively, for "play off", I didn't find anything in any official capacity... and the articles with mention didn't consistently use it as separate words... so I'm thinking it's perhaps fully incorrect (outside of its valid usage as a separate phrase with unrelated meaning)? But with the range of results, and the apparent tendency for it to show up more in the UK, would welcome some further experience from the other side of the pond (or other regions) to confirm that.

[And to make matters worse, the only thread here that really touched on US vs UK hyphenation (When is it appropriate to use a hyphen) had opinion suggesting perhaps the US hyphenates more than the UK?]

grammaticality - "a question by you" or "a question of you"

Is it grammatically correct to say,

"What a silly question of you..."

My friend is trying to convince me that

"What a silly question by you..."

is the only correct way.

Can I use an explicit verb in a comparison clause?

It seems that I often write something like this:

The sizes of these datasets seem to grow faster than the processing power of computers does.

Now, a longish text I'd written was proofread (by a non-professional) and in every case the suggested correction was as follows:

The sizes of these datasets seem to grow faster than the processing power of computers.

(Yes – only the last word was deleted by the proofreader.)

Being a non-native user, I'd like to ask if the way of writing that I've adopted from who-knows-where is always wrong. (Personally, I feel that in some cases – too long sentences maybe – it clarifies my intention slightly.)

Answer

It's not wrong. It's just a stylistic thing, in that "does" doesn't add anything to the sentence, so it might as well be removed.

pronouns - What’s the rule for using “who” and “whom” correctly?

I can never figure out whether I should use who and whom. Most people use who for both colloquially, but some people say this is not correct.

What’s the rule for using who and whom correctly?

Answer

The easy way to tell which is technically correct is to substitute he and him for who and whom, then rearrange the word order to see which sounds right.

“Who were you speaking to?” becomes “You were speaking to he” — which is clearly incorrect.

What is the question for "twice as many ... as" format?

I have a question about how to make a certain type of question.

There is the statement here:

The airplane has twice as many engines as it requires.

I want to make a question the answer to which is:

twice as many engines as it requires

which specifically emphasizes twice as many. Not a yes/no question, but a wh/h question.

---

I asked some native speakers of English and they provided me with sentences like:

How many engines does the airplane have?

or

How many more engines does the airplane have?

But I think the answers to those questions, for example for a plane with 8 engines, are "eight engines", and "four more engines", not "twice as many engines as it requires".

I made the following question but I wonder if it's grammatically correct:

How many times as many engines as required does the airplane have?

Does anyone have a better suggestion?

Answer

Okay, the concept of "times" or "factor" is - if I've read all your comments correctly - critical. So how about:

How many times the required number of engines does this airplane have?

Or:

By what factor does this airplane’s number of engines exceed the requirement?

The answer to both questions cannot be:

The airplane has eight engines.

Nor can it be:

It has four more engines than it requires.

The answer (given a required 4 but extant 8) must be:

The airplane has twice as many engines as it requires.

grammar - Is "group" singular or plural?

When I'm referring to a group of multiple things, should it be considered singular or plural for the purposes of applying a verb to it? For example, which is correct in the examples below?

A sentence is a group of words that is followed by a period.
A sentence is a group of words that are followed by a period.

The group of people constitutes a jury.
The group of people constitute a jury.

A group of crows is called a 'murder'.
A group of crows are called a 'murder'.

My instinct is that it depends on whether the verb is referncing the group itself or the members of the group directly, but is that right?

Answer

According to the OALD, group can actually serve as either a plural or singular noun. The category they give is "countable + singular or plural verb". So, an example of correct use is:

A group of us is/are going to the theatre this evening.

For any of your examples, both is and are can be used. I think the difference between them is as you say: use is when you are referring to the group, and use are when you are referring to the members of a given group. This page on when to use "group" as plural from Washington State University backs this up, saying:

When the group is being considered as a whole, it can be treated as a single entity: “the group was ready to go on stage.” But when the individuality of its members is being emphasized, “group” is plural: “the group were in disagreement about where to go for dinner.”

To analyze your given examples, here are some notes:

• A sentence is a group of words that is followed by a period. Use this form if you're talking about the group itself. That is, a sentence is a group of words followed by a period.


• A sentence is a group of words that are followed by a period. This implies that "This. Is. A. Sentence" is a sentence.


• The group of people constitutes a jury.


• The group of people constitute a jury. This would be more correct, since you are describing the nature of the group.


• A group of crows is called a 'murder'. This would be correct, since you're again describing an entire group.


• A group of crows are called a 'murder'.