How to Make a Complex Sentence Simple

Sometimes, we need to change the structure of a sentence without changing its meaning. In this lesson, you will learn how to change compound sentences into complex sentences.

What is a Complex Sentence?

A complex sentence has one main clause and one or more subordinate (dependent) clauses. These are joined by subordinating conjunctions like because, although, since, when, while, if, though, as, unless, etc.

Example:

  • Although he is poor, he is honest.

What is a Simple Sentence?

A simple sentence has only one subject and one finite verb.

Example:

  • In spite of being poor, he is honest.

Now, let's learn some rules for changing compound sentences into complex ones.

1. Adverbial clauses of time → participial phrases

Explanation: If a complex sentence has a time clause (e.g., when, after, before), you can change it into a present or past participle phrase.

Examples:

1.

  • Complex: When he saw the police, he ran away.
  • Simple: Seeing the police, he ran away.

2.

  • Complex: After he finished his homework, he went to play.
  • Simple: Finishing his homework, he went to play.

3.

  • Complex: Before he left the room, he switched off the fan.
  • Simple: Before leaving the room, he switched off the fan.

4.

  • Complex: When I opened the box, I found a letter inside.
  • Simple: Opening the box, I found a letter inside.

5.

  • Complex: After she had eaten lunch, she went to sleep.
  • Simple: Having eaten lunch, she went to sleep.


2. Replace adjective clauses → participle phrases or adjectives

Explanation: An adjective clause describes a noun. We can often shorten this using a participle phrase.

Examples:

1.

  • Complex: The boy who is playing in the field is my brother.
  • Simple: The boy playing in the field is my brother.

2.

  • Complex: I saw a bird that was flying in the sky.
  • Simple: I saw a bird flying in the sky.

3.

  • Complex: He has a car that was bought last year.
  • Simple: He has a car bought last year.

4.

  • Complex: The girl who won the prize is my sister.
  • Simple: The girl winning the prize is my sister.

5.

  • Complex: The books which are kept on the table are mine.
  • Simple: The books kept on the table are mine.

3. Replace noun clauses (as object) → infinitives

Explanation: When the noun clause functions as an object (after verbs like want, know, ask, decide), change it into an infinitive phrase (to + verb).

Examples:

1.

  • Complex: I want that I should go home now.
  • Simple: I want to go home now.

2.

  • Complex: He decided that he would join the army.
  • Simple: He decided to join the army.

3.

  • Complex: She wishes that she could sing.
  • Simple: She wishes to sing.

4.

  • Complex: We planned that we would start early.
  • Simple: We planned to start early.

5.

  • Complex: They agreed that they would help us.
  • Simple: They agreed to help us.

4. Reason clauses → participle or prepositional phrases

Explanation: If a complex sentence gives a reason (because, since, as), we can often use a participle phrase or prepositional phrase with “because of,” “due to,” etc.

Examples:

1.

  • Complex: Because he was tired, he went to bed early.
  • Simple: Being tired, he went to bed early. / Due to tiredness, he went to bed early.

2.

  • Complex: As it was raining, we stayed indoors.
  • Simple: Owing to the rain, we stayed indoors.

3.

  • Complex: Since he is poor, he cannot buy a car.
  • Simple: Being poor, he cannot buy a car.

4.

  • Complex: As he was late, he missed the train.
  • Simple: Being late, he missed the train.

5.

  • Complex: Because he was ill, he didn’t attend school.
  • Simple: Owing to illness, he didn’t attend school.

5. Purpose clauses → infinitives

Explanation: When a complex sentence has a purpose clause (so that, in order that), we can change it into an infinitive phrase.

Examples:

1.

  • Complex: He studies hard so that he can pass.
  • Simple: He studies hard to pass.

2.

  • Complex: She worked day and night in order that she might earn money.
  • Simple: She worked day and night to earn money.

3.

  • Complex: I exercise regularly so that I may stay fit.
  • Simple: I exercise regularly to stay fit.

4.

  • Complex: They went to the market in order that they might buy vegetables.
  • Simple: They went to the market to buy vegetables.

5.

  • Complex: He shouted loudly so that the driver might hear him.

  • Simple: He shouted loudly to be heard by the driver.

Exercise in Action [Grade 9 & 10]

1. If Clause
  1. If you watch television, you can learn many things. (Simple)
  2. If a student fails in the examination, he suffers from inferiority complex. (Simple)
  3. If we read books, we can enrich our minds. (Simple)
  4. If an examinee answers all the questions, the examiner becomes glad to see that. (Simple)
  5. If we use time properly, we can be benefited. (Simple)
  6. If he makes a proper use of his time, he is sure to prosper in life. (Simple)
  7. Unless one enjoys the beauty of a moonlit night, one cannot explain it properly. (Simple)
  8. Unless you use the morning hours of life, you have to pay a heavy price afterwards. (Simple)
  9. If a student answers all the questions correctly, he will get good marks. (Simple)
  10. We can grow more crops if we can make the best use of rain. (Simple)
  11. No one can receive any reward unless he works hard. (Simple)
  12. If we throw wastage and dirt into water, we make it polluted. (Simple)
2. When / While / After / Before
  1. When I reached there, my friend received me cordially. (Simple)
  2. One night when he was saying his prayer, a thief broke into his room. (Simple)
  3. When we read good books, we discover new worlds. (Simple)
  4. When he was eight years old, his mother died (Simple).
  5. That night, while Ruplal was sleeping, he heard a noise. (Simple)
  6. When I reached there, my friend received me cordially. (Simple)
  7. When he gets the question paper, he should read it carefully. (Simple)
  8. One night when he was saying his prayer, a thief broke into his room. (Simple)
  9. One day when a thief entered his room, he caught him. (Simple)
  10. When a man makes a journey by train, he can enjoy natural scenery. (Simple)
  11. When it is winter, the river remains calm and tranquil. (Simple) 
  12. He sat under the tree and fell asleep. (Simple)
  13. When a student gets the question paper, he should read it attentively. (Simple)
3. Although / Though
  1. Though their weapons were ordinary, they had much courage in their mind. (Simple)
  2. Though we take utmost care, we cannot avoid death. (Simple)
  3. Though we have strict law, we are still affected by this evil. (Simple)
  4. Though we have strict law, we are still affected by this evil. (Simple) 
  5. Though it is a blessing, it has dark sides. (Simple) 
  6. Though there are laws to punish the terrorists, they are not properly applied. (Simple) 
  7. Though she was a nice little girl, she was not an ordinary child. (Simple)
  8. Though cricket is a costly game, people of all classes enjoy playing it. (Simple)
  9. There are two umpires who conduct the game. (Simple)
  10. Though there is law to punish the terrorists, it is not properly applied. (Simple)
  11. Though a healthy man is an asset to his family, an unhealthy man is a liability. (Simple)
  12. Though the moon gives us light, it does not have the light of its own. (Simple)
  13. Though we have strict law, we are still affected by this evil. (Simple)
  14. Though we have strict laws, we are still affected by this evil. (Simple)
4. Relative Pronoun
  1. Suddenly they saw a bear which was coming towards them. (Simple)
  2. The education that he learnt from this institution played better role in his life (Simple).
  3. The man who takes bribe is next to devil. (Simple)
  4. She helped those who were helpless. (Simple)
  5. The freedom fighters who died in the Liberation War are called martyrs. (Simple)
  6. The man who takes bribe, is next to devil. (Simple) 
  7. People who are poor cannot afford to take a balanced diet. (Simple)
5. As/Since/Because
  1. As the demand for flowers is increasing day by day, we should cultivate flower on commercial basis. (Simple)
  2. As they are our real friends, they remain with us in time of danger. (Simple)
  3. People like it as it is cheap. (Simple)
  4. As our farmers use its water for irrigation purpose, they can grow plenty of crops. (Simple)
6. So that
  1. So, a student should be aware of studying regularly and attentively so that he can do well in the examination. (Simple)
  2. We must work hard so that we can earn money. (Simple)
  3. This quality highly motivates á man so that he can sacrifice his life for the country. (Simple)
  4. We must work hard so that we can earn money. (Simple)
7. That
  1. We hope that Bangladesh will be free from this evil. (Simple)
  2. She believes that charity is a great virtue. (Simple)
  3. Its main source is the rain that creates streams, lakes and rivers. (Simple)