So I had to check my friend's homework, but I myself don't even know the answers. For instance:
"Yes, they are. They are both tall and they have both got brown eyes.
"Yes, they are. They are both tall and they both have got brown eyes.
I am leaning towards "they have both got" (#1), but I cannot rationalize why, or why the other option would be bad.
Which is correct, and why?
Edit: Her teacher wasn't exactly of much help when she said that it is just the way it is. The answers are shown below.
A copy of her homework is below:
A copy of the answers (provided by her teacher):
Best Answer
There are six (6) pairs of choices in her homework: that is, six (6) questions. So that gives a total of twelve (12) choices. Of those twelve (12) choices, all except for two (2) are grammatical.
It so happens that four questions have no wrong answer, and only two questions have a right/wrong pair as answers. (Aside: I like that kind of homework!)
CAVEAT: Some of the grammar info that I'm presenting in this post might be intentionally--or unintentionally--over simplified. Hopefully there won't be any egregious errors. (I'm sure I'll get dinged if there are.)
Let's first do a little grammar review, and then later we'll look at her homework.
There are two main uses for the word "both":
One: a marker of coordination -- This is usually taught in a formal lesson. The word "both" is used to mark the first coordinate of an and-coordination of two coordinates. E.g. "He likes both apples and pears", "He likes to both run track and swim relays". This type of use is rather straightforward, and it is a basic topic taught in schools.
Two: a quantificational adjunct -- This might only be lightly taught in a formal lesson, or maybe perhaps not taught at all. The word "both" is functioning as an adjunct, which is a modifier that is optional for a given sentence. It could be omitted with no loss, or almost no loss, in meaning (usually). It behaves in a similar fashion as traditional grammar's "adverbials" (which are also adjuncts), e.g. "They would both/quickly run to school in the mornings".
It is usually possible for a speaker to place a quantificational adjunct right after the subject. (e.g. "We both can sing tonight".)
When a clause is headed by an auxiliary verb, then a speaker can usually place an adjunct right after that verb; and often there could be a preference to have the adjunct located after an auxiliary. (e.g. "They would both/quickly run to school in the mornings".)
When a clause is headed by a transitive lexical verb, then there will often be some resistance to having an adjunct located between the verb and its object. (e.g. * "They play both the guitar", which is ungrammatical.)
Auxiliary verb: An auxiliary verb can usually be identified by verifying that it can participate in subject-auxiliary (verb) inversion. For example:
"They are tall" has the subject-aux inversion of "Are they tall?"
"They can run fast" has the subject-aux inversion of "Can they run fast?"
For those above examples, the auxiliary verbs are "are" and "can". The auxiliary verbs switched spots with the subjects when they underwent inversion.
Sometimes it might be unclear as to whether the word "both" is functioning as a quantificational adjunct or as a marker of coordination. Consider this possible ambiguous example:
The two different interpretations can be seen when it is compared against:
"She can both sing and dance." -- [marker of coordination]
"We can both sing." -- [quantificational adjunct]
Now let's evaluate the example choices by question.
Question #1:
The above two examples are grammatical because the word "both" is functioning as quantificational adjunct in both.
That is: in #1.a, the word "both" is after the auxiliary verb "are", and in #1.b, the word "both" is after the subject. And both locations are valid slots for the quantificational adjunct "both".
Question #2:
The above two examples are grammatical because the word "both" is functioning as quantificational adjunct in both.
That is: ditto as given for question #1 above, except that the auxiliary verb here is the verb "have".
Question #3:
Example #3.a is grammatical because the word "both" is functioning as a quantificational adjunct. The reason is the same as given for example #1.b above: that is, the word "both" is after the subject.
Example #3.b is ungrammatical. The reason it is bad is because the word "both" is functioning as a quantificational adjunct, but it is located after a transitive lexical verb ("like") and before its object.
Question #4:
Example #4.a is ungrammatical. The reason it is bad is because the word "both" is functioning as a quantificational adjunct, but it is located after a transitive lexical verb ("play") and before its object.
Example #4.b is grammatical because the word "both" is functioning as a quantificational adjunct. The reason is the same as given for example #1.b above: that is, the word "both" is after the subject.
Question #5:
The above two examples are grammatical because the word "both" is functioning as quantificational adjunct in both.
That is: ditto as given for question #1 above.
Question #6:
The above two examples are grammatical, but the first of the pair is ambiguous as to how it could be interpreted.
Example #6.a is grammatical because of one of the following reasons:
The word "both" could considered to be functioning as a quantificational adjunct that is located after the auxiliary verb "are". Which is the same reason as given for example #1.a above.
Or the word "both" could be considered to be a marker of coordination, where the two coordinates are "lively" and "confident".
Example #6.b is grammatical because the word "both" is functioning as a quantificational adjunct. The reason is the same as given for example #1.b above: that is, the word "both" is after the subject.
EXTRA INFO: Some related grammar excerpts
The 2002 CGEL, page 1305:
The 2002 CGEL, page 102:
The 2002 CGEL, page 413:
The 2002 CGEL, page 428:
Some related examples from the 1998 SPE. An example is grammatical if it is unmarked (most of the examples below are grammatical).
Page 98, #2:
Page 170, #10:
The children all must have fallen asleep.
The children must all have fallen asleep.
The children must have all fallen asleep.
Page 244, #5:
Page 245, #6:
Page 521, #2:
NOTE: The 2002 CGEL is the 2002 reference grammar by Huddleston and Pullum (et al.), The Cambridge Grammar of the English Language.
NOTE: The 1998 SPE is the 1998 textbook by James D. McCawley, The Syntactic Phenomena of English, 2nd edition, paperback.
OLD NOTES:
A related topic is quantificational adjuncts, which is discussed in the 2002 CGEL, pages 102, 413, 428.
I did a quick look at the teacher's answers. There are a number of grammar issues in play: such as, transitive verbs (e.g. "play") have a resistance to having some kinds of adjunct (e.g. "both") between the verb and its object. Also complicating the issue is that the word "both" can be a marker of coordination, e.g. "She plays both the guitar and piano".