Verified answer

The subordinate clause in your sentence is:

that many people can’t name the last five presidents

Notice how "that many people can't name the last five presidents" can't stand on its own as a sentence because it begins with a subordinating conjunction, "that". The main clause in your sentence is "Did you know". A subordinate clause—also called a dependent clause—will begin with a subordinate conjunction or a relative pronoun and will contain both a subject and a verb. This combination of words will not form a complete sentence. It will instead make a reader want additional information to finish the thought.

Here is a list of subordinate conjunctions:

after

although

as

because

before

even if

even though

if

in order that

once

provided that

rather than

since

so that

than

that

though

unless

until

when

whenever

where

whereas

wherever

whether

while

why

Here are your relative pronouns:

that

which

whichever

who

whoever

whom

whose

whosever

whomever

See:

http://www.chompchomp.com/terms/subordinateclause....

http://en.wikipedia.org/wiki/Dependent_clause

http://www.english-grammar-revolution.com/subordin...