I want to know what are the characteristics of the subject and predicate of English sentences, and what corpus tools should I use?

The subject is the theme of the sentence, and it is the subject of the sentence. Its position is usually at the beginning of a sentence. Words, phrases, clauses and even sentences can be used as subjects. However, in interrogative sentences, or when negative words, adverbs indicating place or time, adverbs of degree and predications are placed at the beginning of the sentence, the subject should be placed after the predicate, which is called inverted sentences.

1) noun as the subject. For example:

A tree fell across the road. A tree fell across the road.

Small rivers provide water for big rivers. A small river flows into a big river.

2) Pronouns are the subject. For example:

You are not far wrong. You are almost right.

He told a joke, but it didn't work. He told a joke, but it didn't make people laugh.

3) Numerals are the subject. For example:

Three is enough. Three is enough.

Seven MINUS four leaves three. Seven minus four equals three.

4) Nominalization adjectives as the subject. For example:

Idlers are forced to work. Lazy people are forced to work.

Old and young March side by side. Old and young walk side by side.

5) Adverbs as the subject. For example:

Now is the time. Now is the time.

Do it carefully. Be careful.

6) Nominalization preposition as the subject. For example:

The ups and downs of life must go with the times. We must bear the ups and downs of life.

This book is difficult to read. This book is difficult to read.

7) infinitive is the subject. For example:

Finding your way may be a problem. Whether you can find the way may be a problem.

Nice to see him again.

8) Gerund as the subject. For example:

Smoking is harmful to you. Smoking is harmful to you.

Watching movies is a pleasure, and making movies is a hard job. Watching movies is a pleasure, but making movies is hard work.

9) Nominalized past participle as the subject. For example:

Disabled people will get more money. Disabled people will get more benefits.

The fallen die of old age. The deceased died of old age.

10) prepositional phrase as the subject. For example:

It's not far to Beijing. It's not far from Beijing.

It takes three hours to ride from Yan 'an to Nanniwan. It takes three hours to ride from Yan 'an to Nanniwan.

1 1) as the subject, that is, the subject clause. For example:

Just when you're ready. You can always be ready.

Just because Sally wants to leave doesn't mean we have to leave. We can't say that just because Sally is leaving, we have to leave.

A subject can be composed of more than one noun (pronoun), and this subject can be called a coordinate subject. For example:

He and I are old friends. He and I are old friends.

The party and the government are very concerned about our welfare. The party and the government are very concerned about our lives.

English often uses impersonal nouns as subjects. For example:

A gun wounded him. Someone wounded him with a gun.

The good news brought them all to my home. They all came to my house after hearing the good news.

English also often uses words indicating time and place as subjects. For example:

"Today is your last French class," said Mr. Hamel. "Today is your last French class." Mr. Hamel said. (alphonse Dowday)

Tiananmen Square saw our five-star red flag rising on1October 6 for the first time, and our first five-star red flag rose in Tiananmen Square.

Like Chinese, English subjects are sometimes illogical. For example:

The kettle is boiling. The kettle is boiling.

My tent can sleep four people.

Sometimes, in spoken English, for emphasis or supplement, the speaker often repeats the subject with nouns (or pronouns). For example:

Your friend Johnson is a good man. Your friend Johnson is a good man.

The poison worked. The poison worked.

It's good to see you after all this time. It's great to see you again after such a long time.

Sometimes nouns (or pronouns) with repetitive subjects can take be, have or auxiliary verbs. For example:

Your game is too much. That's too much. Your tricks are too much.

He's happy, really. He's so happy, so happy. (he was can also be a separate sentence, which is called He was)

I hope it can help you solve the problem.