Grammatically Correct: The writer's essential guide to punctuation ...

GRAMMATICALLY CORRECT
possible to omit the conjunction, since it could easily be inferred.
If this is done, the comma is no longer the right separator, since
putting it between two independent clauses would create a comma
splice. The semicolon is the proper mark instead. In this role, it acts
as a sort of stand-in for the missing conjunction, sending a signal
to readers that there is some implicit and self-evident relationship
between the clauses it separates.
His offer sounded too good to be true; I didn't believe it.
Doreen was starting to worry; Leo was now two hours late.
We didn't have the heart to continue; it all seemed so futile.
Sol is the practical one in the family; his brother is the dreamer.
Aside from shaving off a word, an advantage to omitting conjunctions
is that an over-exactitude in spelling everything out can render
your style a bit ponderous. Writing often comes through as subtler,
more sophisticated, if you leave a few blanks for your readers to
fill in for themselves. (For other strategies, see the discussions of
elliptical constructions on page 85 and the suspension hyphen on
page 135.)
Of course, omitting conjunctions isn't appropriate in all cases.
Sometimes a conjunction couldn't easily be inferred, and a sentence
might look puzzling without it.
She longed to stay till the end of the talk; she had to leave.
The connection between these clauses isn't immediately obvious,
so the sentence comes through as mildly confusing. It may be a bit
of a strain for a reader to deduce that the missing conjunction must
be yet or but.
In other cases, different conjunctions might be possible, so omitting
the intended one might cause a reader to put the wrong interpretation
on the sentence.
The task clearly would be difficult; I would have a day to do it.
Is the missing word here and? but? since? so? Is one day plenty
of time or not enough time? In the absence of a conjunction, the
intention of the second clause could be misconstrued. Other parts
of the text might provide enough context to clarify the writer's
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