• after*
• although
• as*
• as far as
• as though
• because
• before*
• even if
• even though

• if
• inasmuch as
• in case (that)
• in order (that)
• insofar as
• in that
• lest
• no matter how
• now that
• once

• only if
• provided (that)
• since*
• supposing that
• than****
• though

• till
• unless
• until*
• when
• whenever
• where**
• wherever
• whereas
• whether or not
• while

* Words marked with a single asterisk can also function as prepositions.

** The word “where” is more commonly used to introduce an adjective clause or a noun clause.

*** These pairs express “degree” and do not follow the usual pattern.

**** The conjunction “than” is unusual in that the predicate of the subordinate clause is often omitted.