Joining of Sentences (Synthesis) — A Comprehensive Guide

Joining of sentences (also called Synthesis) means combining two or more simple sentences into one meaningful sentence without changing the core meaning. ISC and ICSE papers test this under Section A (Grammar), usually asking students to join sentences as directed or to choose the most appropriate method.

Part A: Joining into a Simple Sentence

A Simple Sentence has one subject and one finite verb. We reduce one of the clauses into a phrase or word to achieve this.

Method 1: Using an Infinitive (to + base verb)

Use when the second sentence expresses purpose, intention, or possibility. Drop the subject of the second sentence and replace with to + verb.

Two Sentences	Joined (Simple)
He works hard. He wants to pass the exam.	He works hard to pass the exam.
She has a piano. She wants to learn it.	She has a piano to learn.
The child is very young. She cannot go to school.	The child is too young to go to school.
He studies hard. He hopes to top the class.	He studies hard to top the class.

Note: When the first sentence implies excess, use too...to; when it implies sufficient ability, use enough...to.

She is very weak. She cannot lift it. → She is too weak to lift it.
She is strong enough. She can carry it. → She is strong enough to carry it.

Method 2: Using a Participle

A participle is a verb form used as an adjective. Use this method when both sentences share the same subject.

Type	Two Sentences	Joined
Present Participle (verb+ing)	She was singing. She entered the hall.	Singing, she entered the hall.
Past Participle	He was exhausted. He fell asleep.	Exhausted, he fell asleep.
Perfect Participle (Having/Being + past participle)	He finished the work. He went home.	Having finished the work, he went home.
Perfect Participle (Passive)	The letter was written. It was posted.	Having been written, the letter was posted.

⚠ Common Error: Do NOT use a participle if subjects of both sentences differ. "Walking down the road, a car hit him" is a dangling participle — WRONG.

Method 3: Using a Gerund (verb+ing as noun)

A gerund turns a verb into a noun. It is placed as the subject or object of the joined sentence.

He smokes. It is a bad habit. → Smoking is a bad habit.
He told lies. This annoyed everyone. → His telling lies annoyed everyone.
She practises daily. She aims to improve. → She aims to improve by practising daily.

Method 4: Using a Noun/Noun Phrase (Appositive)

One sentence is reduced to a noun or noun phrase placed beside the subject of the other.

Rabindranath Tagore was a great poet. He wrote Gitanjali. → Rabindranath Tagore, a great poet, wrote Gitanjali.
Ms Sharma is our principal. She addressed the students. → Ms Sharma, our principal, addressed the students.

Method 5: Using an Adjective or Adverb

Reduce one sentence to a single descriptive word that modifies a noun or verb.

The traveller was tired. He sat down to rest. → The tired traveller sat down to rest.
He answered the question. His answer was correct. → He answered the question correctly.

Method 6: Using a Prepositional Phrase

Convert one sentence into a phrase beginning with a preposition (in, on, at, by, despite, in spite of, because of, etc.).

He was ill. He could not attend school. → Because of his illness, he could not attend school.
She was tired. Yet she continued working. → Despite her tiredness, she continued working.
It rained heavily. The match was cancelled. → Due to heavy rain, the match was cancelled.

Method 7: Using the Nominative Absolute Construction

This combines two sentences with different subjects using noun + participle at the start. No conjunction is needed.

The rain stopped. We went out for a walk. → The rain having stopped, we went out for a walk.
The lesson was over. The students left the classroom. → The lesson being over, the students left the classroom.
The bell rang. The players ran to the field. → The bell having rung, the players ran to the field.

Part B: Joining into a Compound Sentence

A Compound Sentence has two or more independent clauses joined by a coordinating conjunction (FANBOYS: for, and, nor, but, or, yet, so) or a semicolon.

💡Please be informed that in ICSE exam, joining with 'and', 'but' or 'so' is not allowed. Still we include it just for educational purpose.

Conjunction	Use	Example
and	Addition	She sang and he played the piano.
but	Contrast	He is poor but honest.
or	Alternative	Hurry up or you will miss the train.
nor	Negative alternative	He did not come nor did he send a message.
for	Reason	He rested early, for he was tired.
yet	Unexpected contrast	She tried hard, yet she failed.
so	Result	It rained, so the match was cancelled.

Correlative Conjunctions

These work in pairs and appear in both clauses:

Pair	Example
both … and	She is both clever and hardworking.
either … or	Either he comes or I leave.
neither … nor	He is neither punctual nor sincere.
not only … but also	She is not only intelligent but also kind.
no sooner … than	No sooner did he arrive than it began to rain.
hardly/scarcely … when	Hardly had she left when it began to snow.

Part C: Joining into a Complex Sentence

A Complex Sentence has one main (independent) clause + one or more subordinate (dependent) clauses joined by a subordinating conjunction or relative pronoun.

Method 1: Using Subordinating Conjunctions

Type	Conjunctions	Example
Time	when, while, after, before, until, as soon as, since	She wept when she heard the news.
Cause/Reason	because, since, as	He stayed home because he was ill.
Condition	if, unless, provided that, in case	You will fail unless you work hard.
Contrast	though, although, even though, while	Although it rained, they played.
Purpose	so that, in order that, lest	Study hard so that you may pass.
Result	so…that, such…that	He was so tired that he slept at once.

Method 2: Using Relative Pronouns (Adjective Clause)

Use who / whom / whose / which / that / where / when to join two sentences where one gives extra information about a noun in the other.

Two Sentences	Joined
The man called. He is my uncle.	The man who called is my uncle.
I lost the pen. My father gave it to me.	I lost the pen which my father gave me.
She met a girl. The girl's mother is a doctor.	She met a girl whose mother is a doctor.
This is the house. Tagore was born here.	This is the house where Tagore was born.
I remember the day. We first met then.	I remember the day when we first met.

Method 3: Using Noun Clauses

One sentence becomes a noun clause (subject or object) introduced by that, what, whether, if, how, why, when, where.

He said something. He would return soon. → He said that he would return soon.
Is he honest? Nobody knows. → Nobody knows whether he is honest.
She asked a question. Where had I been? → She asked where I had been.

Part D: Special Constructions (ISC Focus)

1. So … that / Such … that

Structure: so + adjective/adverb + that OR such a/an + adjective + noun + that
She spoke very softly. Nobody could hear her. → She spoke so softly that nobody could hear her.
It was a very cold day. We stayed indoors. → It was such a cold day that we stayed indoors.

2. Too … to / Enough … to

He is very old. He cannot run. → He is too old to run.
She is quite strong. She can carry this. → She is strong enough to carry this.

3. No sooner … than / Hardly/Scarcely … when

He reached. It began to rain. → No sooner had he reached than it began to rain.
She left. The guests arrived. → Hardly had she left when the guests arrived.
⚠ Note: These sentences begin with inverted (question-like) word order: had/was/were + subject.

4. Unless

Unless = if…not. Never use "not" with unless.
If you do not study, you will fail. → Unless you study, you will fail.

5. Not only … but also

She is intelligent. She is also kind. → She is not only intelligent but also kind.
⚠ When placed at the start: Not only did she win, but she also broke the record. (inversion required)

6. Despite / In spite of

Followed by noun/gerund, NOT a clause (no subject + verb after "despite").
Although it rained, they played. → Despite the rain, they played. / In spite of the rain, they played.
Even though she was tired, she worked. → Despite being tired, she worked.

7. As soon as

He reached the station. The train left immediately. → As soon as he reached the station, the train left.

8. Lest … should

Walk carefully. You may fall. → Walk carefully lest you should fall.
⚠ Always use "should" after "lest"; never "not".

Part E: Quick-Reference Summary

Method	Sentence Type	Key Words
Infinitive	Simple	to, too…to, enough…to
Participle	Simple	-ing, -ed, having + past participle
Gerund	Simple	verb+ing as noun
Appositive / Noun Phrase	Simple	comma + noun phrase
Adjective/Adverb	Simple	single describing word
Prepositional Phrase	Simple	despite, due to, because of
Nominative Absolute	Simple	Noun + having + past participle
Coordinating Conjunction	Compound	and, but, or, so, yet, for, nor
Correlative Pair	Compound	either…or, neither…nor, not only…but also
Subordinating Conjunction	Complex	because, if, unless, although, when, so that
Relative Pronoun	Complex	who, which, whose, where, when
Noun Clause	Complex	that, whether, how, what, why
Special Constructions	Complex/Compound	so…that, no sooner…than, hardly…when, lest

Last updated: February 21, 2026

Portions of this article were developed with the assistance of AI tools and have been carefully reviewed, verified and edited by Jayanta Kumar Maity, M.A. in English, Editor & Co-Founder of Englicist.

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