So vs Therefore: Informal vs Formal
B1-B2 Level
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In everyday conversation, so is perfectly natural and nobody will judge you for using it. In essays, reports, and academic writing, therefore sounds more professional and precise. Therefore can also appear in mid-sentence position after the subject: "I was therefore unable to attend the meeting." This mid-position use is particularly common in formal and academic English. A common mistake is using "so" to start a sentence in formal writing — while it is becoming more accepted, "therefore" or "consequently" remain the better choices for essays and exams. Learning to switch between informal and formal result connectors is an important skill for B1-B2 learners.
Quick Rule
cause, so + result (informal) | Cause. Therefore, + result (formal)
- 1.The shop was closed, so we went somewhere else. (informal — everyday speech)
- 2.All the evidence supports the theory. Therefore, we can accept it as valid. (formal — academic)
- 3.She didn't study, so she failed the test. (informal — negative cause)
- 4.The road was blocked. We therefore took an alternative route. (formal — mid-position)
- 5.It wasn't raining, so I didn't take an umbrella. (informal — double negative context)
All 20 questions
Complete the sentences with 'so' or 'therefore'. Both mean the same thing - the difference is FORMALITY. Decide from the sentence style whether it's informal or formal.
I was really tired, _____ I went to bed early.
The data was inconclusive. _____, further research is required.
The patient showed no improvement. _____, we changed the treatment protocol.
It started raining, _____ we just stayed inside.
I forgot my umbrella, _____ I got completely soaked!
Sales declined by 15% in Q3. _____, cost reduction measures must be implemented.
The café was packed, _____ we ended up going somewhere else.
The hypothesis was not supported by empirical evidence. _____, it must be rejected.
The submission deadline has elapsed. _____, your application cannot be processed.
He didn't study at all, _____ he totally failed the exam.
The preliminary results indicate a positive trend. _____, we recommend continued investment.
I don't have any cash on me, _____ I can't lend you any.
My car broke down this morning, _____ I had to take the bus.
The defendant breached clause 4.2 of the contract. _____, the plaintiff is entitled to damages.
The allocated budget has been reduced by 20%. _____, certain projects will be postponed.
She was starving, _____ she made herself a quick sandwich.
The risk analysis identified several critical vulnerabilities. _____, immediate action is advised.
The shop was already closed, _____ I'll just go back tomorrow.
It was getting pretty late, _____ we decided to head home.
The evidence presented is insufficient to establish liability. _____, the case is hereby dismissed.
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