subject, the second predicate,
and the second copula must be supplied. This can always be done from the
first proposition,--_he likes you better than me_ = _he likes you better
than he likes me_. The compendious expression of the second proposition is
the first point of note in the syntax of conjunctions.

s. 504. The second point in the syntax of conjunctions is the fact of their
great convertibility. Most conjunctions have been developed out of some
other part of speech.

The conjunction of comparison, _than_, is derived from the adverb of time,
_then_: which is derived from the accusative singular of the demonstrative
pronoun.

The conjunction, _that_, is derived also from a demonstrative pronoun.

The conjunction, _therefore_, is a demonstrative pronoun + a preposition.

The conjunction, _because_, is a substantive governed by a preposition.

One and the same word, in one and the same sentence, may be a conjunction
or preposition, as the case may be.

_All fled but John_.--If this mean _all fled_ except _John_, the word _but_
is a preposition, the word _John_ is an accusative case, and the
proposition is single. If instead of _John_, we had a personal pronoun, we
should say _all fled but_ him.

_All fled but John_.--If this mean _all fled but John did not fly_, the
word _but_ is a conjunction, the word _John_ is a nominative case, and the
propositions are two in number. If, instead of _John_, we had a personal
pronoun, we should say, _all fled but_ he.

From the fact of the great convertibility of conjunctions it is often
necessary to determine whether a word be a conjunction or not. _If it be a
conjunction, it cannot govern a case. If it govern a case it is no
conjunction but a preposition._ A conjunction cannot govern a case, for the
following reasons,--the word that follows it _must_ be the subject of the
second proposition, and as such, a nominative case.

s. 505. The third point to determine in the syntax of conjunctions is the
certainty or uncertainty in the mind of the speaker as to the facts
expressed by the propositions which they serve to connect.

1. Each proposition may contain a certain, definite, absolute fact--_the
day is clear_ because _the sun shines_. Here there is neither doubt nor
contingency of either the _day being clear_, or of the _sun shining_.

Of two propositions one may be the condition of the other--_the day will be
clear_ if _the sun shine_. Here, although it is certain that