The verb in the sentence with a subordinate clause must agree with the subject of the whole sentence, not with a noun in the subordinate clause. Subordinate clauses can begin with the words that, which, who, and whom.

Not:The children who live in that house is a terror!
But:The children who live in that house are a terror!

Not:San Francisco, which has many lovely neighborhoods, are exciting to visit.
But:San Francisco, which has many lovely neighborhoods, is exciting to visit.

Third person singular verbs follow indefinite pronouns.

Anything

looks

[not look] good with black slacks.

Everybody

pays

[not pay] taxes.

The

sisters

don't

have

pets,

but

neither

dislikes

[not dislike] animals.

At

the

game's

end,

nobody

was

[not were] in the stands.

Someone

leaves

[not leave] the window open every night.

Something

isn't

[not aren't] right here.