A compound sentence can be converted into a simple sentence by reducing the number of clauses to one.

Read the examples given below:

Compound: He got up and walked away.
Simple: Getting up, he walked away.

Here we reduce the clause ‘he got up’ into the participial phrase ‘getting up’.
More examples are given below:

Compound: He must return the money, or he will be punished.
Simple: He must return the money to escape punishment.

Here we reduce the clause ‘or he will be punished’ into the infinitive phrase ‘to escape punishment’.

Compound: They not only looted the shop but also set fire to it.
Simple: Besides looting the house, they also set fire to it.

Here the coordinate clause ‘they not only looted the house’ is reduced to the prepositional phrase ‘besides looting the house’.

Compound: He ran away and thus escaped punishment.
Simple: He ran away in order to escape punishment.

Here the clause ‘thus escaped punishment’ is replaced by the infinitive phrase ‘in order to escape punishment’.

Thus we have seen that compound sentences can be changed to simple sentences by reducing clauses to participial, prepositional or infinitive phrases.

Exercise

Convert the following compound sentences into simple sentences

1.    You must run fast, otherwise you cannot catch the train.
2.    The rain stopped and we continued our journey.
3.    He is rich, yet he is unhappy.
4.    You must not repeat this, otherwise you will be punished.

Answers

1.    You must run fast in order to catch the train.
2.    The rain having stopped we continued our journey.
3.    Despite being rich he is unhappy.
4.    You must not repeat this in order to escape punishment.