Preposition plus object

Preposition objects are nouns, noun phrases, even object clauses, or some pronouns placed after prepositions.

summary of usage: under normal circumstances, prepositions must have their own objects. There are many elements that can act as prepositional objects.

usage classification:

1. Nouns or pronouns as prepositional objects

He never goes out at night. He never goes out at night.

Don't hide behind others. Don't hide behind others.

The town is the seaside. The town is located by the sea.

Note: If personal pronouns are used as prepositional objects, you should pay attention to the objective case.

He got there before me. He got there before me. (you can't use before I)

2. Gerund (phrase) as prepositional object.

She is quick at learning languages. She learns languages quickly.

He makes a living by teaching. He teaches for a living.

crossing the street he was running over. He was knocked down by a car while crossing the street.

3. Clause as prepositional object

He was surprised at what she said. He was surprised to hear what she said.

he began to think about what he would do. He began to think about what he should do.

note: prepositions are usually not followed by that clause, but the preposition except? Is the exception. I know nothing about him except that he is from Paris. I only know that he is from Paris, but I don't know anything else.

in addition, the preposition is not followed by an if clause as the object, which is available in this case? whether。 We are worried about what he will come. We are worried about whether he will come.