Words and phrases in sentences can be divided into sentence elements based on their use. There are six kinds of sentence elements in Chinese:
1. Subject
2. Predicate
3. Object
4. Attributive
5. Adverbial adjunct
6. Complement

The Predicate

The predicate makes a statement about the subject. The predicate is usually placed after the subject. All kinds of notional words and most types of phrases can act as the subject.

他自己开车去 (tā zìjǐ kāi chē qù)。He will drive there by himself. ( The verb "开车去" is the predicate)
天黑了 (tiān hēi le)。It is dark now. (The adjective "黑" is the predicate)
我今年十八 (wǒ jīnnián shíbā)。This year I am eighteen years old. (The number "eighteen" is the predicate)

The predicate can be followed by objects. For instance,
我开车 (wǒ kāi chē)。I am driving a car. (One object)
他送我花 (tā sòng wǒ huā)。He gave me a bunch of flowers. (Two objects)

When an adjective acts as the predicate the adverb "很" (hěn) is usually used. Otherwise, a comparison is implied.
这个城市很小 (zhègè chéngshì hěn xiǎo)。This is a small city.
这个城市小 (zhègè chéngshì xiǎo)。This city is smaller than that one.