The subject usually comes before the verb, but there are sentences that have the subjects coming after the verbs. The verbs must still agree with the subjects.
- There is a fly on your forehead.
- There were three big men seated at the next table staring at me.
In questions, the subjects usually come after the verbs.
- Does your girlfriend know you have a string of ex-girlfriends?
- Have you heard my new ghost story yet?