Are the singular and plural nouns before and after or consistent?

The singular and plural nouns before and after or are often the same. According to the principle of subject-predicate agreement, the key depends on the number of predicate verbs or copula verbs. The principle of consistency of predicate verbs means that if there are two or more subjects in a sentence, the singular and plural forms of predicate verbs should be determined according to the singular and plural forms of adjacent subjects.

The usage of or is summarized as 1, which means to choose, meaning "or" or ":

Is he asleep or awake? Is he asleep or awake?

Are you going to America by boat or by plane? Are you going to America by boat or by plane?

You can go or stay, it's up to you. It's up to you to go or stay.

Are you from North China or South China? Are you from North China or South China?

You can come now or meet us there later. You can come now or meet us there later.

2, said negative conditions, meaning "otherwise":

Hurry up, or we will be late. Hurry up, or we will be late.

Hurry up, or you will be late for school. Hurry up, or you will be late for school.

Wear warm clothes, or you will catch a cold. Wear warm clothes, or you will catch a cold.

Be careful, or you will break that vase! Be careful, or you will break that vase!

Cross the road very carefully. Look both ways, or you may be knocked down. Be very careful when crossing the road, and watch both sides, or you will be knocked down by a car.

3. It can mean "or":

He must be joking, otherwise he is crazy. He must be joking, otherwise he is crazy.

The book must be here, or you will have lost it. The book must be here, or you will have lost it.

4, used in negative sentences instead of and:

He is neither clever nor handsome. He is not smart, and he is not good-looking.

Comparison:

They sing and dance. They sing and dance.

They don't sing or dance. They don't sing or dance.