To nest one of the sentences inside the other easily, it is easiest if
we add a subordinating conjunction at the front of the clause that will
become nested (this specifies the used of the nesting semantically). Let's
assume that we will nest 'Mary kissed John' inside 'John kissed Mary'
to specify a cause-and-effect relation between the two actions. We can
do this by putting 'because' at the front of 'Mary kissed John'. Because
English is not keen on repeating words too much in complex structures,
it will be more natural if we also substitute the pronoun 'him' for 'John'
in the clause to be nested.
So, try nesting 'because Mary kissed him' inside
'John kissed Mary'. See how many different places you can make the nesting
happen (don't forget that you can nest at the end as well as in the middle
of the structure).
Our Answer
We can think of three reasonably natural possibilities. Given the wording
of the task, perhaps the most obvious is:
John, because Mary kissed him, kissed
Mary.
But you could also get:
Because Mary kissed him, John kissed
Mary.
John kissed Mary because Mary kissed
him.
Note that in all these cases, the ordering of the kissed is the same,
no matter what the ordering in the sentence!
We have use the subordinating conjunction 'because' which indicates
a causal connection, but if we had used a different subordinating conjunction
(e.g. 'when', 'while', 'if', 'so that' etc) we would have altered the
semantic relationship between the clauses (to 'immediately after/at
the same moment in time', 'together during a longer stretch of time',
and so on).
