The simple predicate in a sentence is the main verb plus any helping verbs. Together, they're called a verb phrase.
Got modifiers? Forget about 'em. The simple predicate doesn't include any modifiers. They don't have to show you no stinkin' modifiers.
"Susan and Sarah will open their Christmas presents at 4:30 in the morning whether their parents like it or not."
There's no such thing as "too early" when it comes to ripping the wrapping paper off a brand-new Barbie Dream House. In this sentence, the main verb, open, plus the helping verb, will, create the verb phrase will open, which is the simple predicate.
"Ann had never camped before."
In this example, the main verb, camped, plus the helping verb, had, join forces to create the verb phrase had camped, which is the simple predicate.
"Dinosaurs roamed the Earth for 165 million years."
That's a mighty long time. We puny little humans have only been around for about two million years. In this example, roamed is the main verb, and there are no helping verbs, so roamed is the simple predicate.
The complete predicate of a sentence includes all of the words that tell the reader what the subject is or does: the main verb, helping verbs, modifiers, and all of the words that complete its meaning.
"Shane shoveled his initials into the snowy driveway."
We admire Shane's creativity, but it's not going to make getting the car out of the garage much easier. Here, the complete predicate is made up of shoveled, which is the main verb, and then all of the words that modify shoveled.
"Lacey composed an original rap about mitochondria for extra credit in her biology class."
What rhymes with mitochondria? Sadly, basically nothing.
What's the complete predicate in this sentence? That's right: it's the main verb, composed, and then all of the words that complete its meaning.
"The boys surf Turtle Toes Cove every Saturday morning."
In this gnarly example, the main verb, surf, plus all of the words that complete its meaning, create the complete predicate. Those boys should watch out for sharks, though.
A compound predicate has two or more predicates linked with a coordinating conjunction, a.k.a. one of the FANBOYS (For, And, Nor, But, Or, Yet, So). Yeah, there's no way to make that sentence less dry—it's the Melba Toast of sentences. Check out our examples, though: they'll clear things up.
"Damien took his speech teacher's advice and imagined that the audience members were all naked."
In this example, took and imagined form a compound predicate because they're both actions that Damien performed before addressing the crowd at his grandmother's retirement community. Ew.
"Keira will order the hot tub and stay home from work on Friday to wait for the delivery guy."
Party at Keira's! In this bubbly sentence, will order and stay form the complete predicate because they're both actions Keira will perform. Other actions that Keira will later perform include "being super relaxed" and "sleeping like a baby."
"Neil snores and drools in his sleep."
Here, snores and drools form the complete predicate because the two actions are both utterly charming things that Brian does while sleeping.