Simple explanation
What do so and such mean? So and such are commonly used to add emphasis. They can show that a quality, amount, or situation is especially strong or noticeable. The main difference is grammatical: so normally comes before an adjective or adverb, while such normally comes before a noun phrase. Compare so beautiful with such a beautiful place. When do we use so? Use so when you want to emphasize an adjective or adverb. In The room is so quiet, so strengthens the adjective quiet. In She speaks so clearly, it strengthens the adverb clearly. A useful B1 rule is to look at what comes immediately after the word: if it is an adjective or adverb without a noun phrase, so is usually the right choice. When do we use such? Use such before a noun phrase. With a singular countable noun, the usual pattern is such + a/an + adjective + noun, as in such a difficult question. With plural nouns and uncountable nouns, do not use a/an: such friendly people, such useful information, and such terrible weather. An adjective is not required: such a surprise is also correct. Using so ... that and such ... that to express a result So and such can be followed by a that-clause when you want to explain the result of an extreme quality or situation. In The coffee was so hot that I couldn't drink it, so emphasizes hot and the that-clause gives the result. In It was such a hot day that we stayed inside, such introduces the noun phrase a hot day and the that-clause gives the result. So much, so many, so few, and so little Quantity expressions follow an important pattern with so. Use so many and so few with plural countable nouns: so many messages, so few opportunities. Use so much and so little with uncountable nouns: so much work, so little time. These patterns are important exceptions to the simple idea that a following noun automatically requires such. Using so and such in statements, negatives, and questions The basic patterns work in different sentence types. In statements, you can say The test was so difficult or It was such a difficult test. In negative sentences, you might say I didn't expect it to be so expensive. In questions, you can ask Why are you so tired? or Why was it such a stressful meeting? The choice between so and such still depends on the structure that follows.
Grammar formula
So with an adjective
so + adjectiveThe room is so quiet.
So with an adverb
so + adverbShe speaks so clearly.
Such with a singular countable noun
such + a/an + adjective + singular countable nounIt was such a good idea.
Such with a plural noun
such + adjective + plural nounThey are such friendly people.
Such with an uncountable noun
such + adjective + uncountable nounWe had such bad weather.
Result with so
so + adjective/adverb + that + clauseI was so tired that I went straight to bed.
Result with such
such + noun phrase + that + clauseIt was such a difficult exam that many students couldn't finish it.
Countable quantity
so many/few + plural countable nounThere were so many people at the station.
Uncountable quantity
so much/little + uncountable nounWe had so little time.
Core rules
- 1
Use so before an adjective
Use so + adjective when emphasizing a quality: so tired, so expensive, so difficult.
- 2
Use so before an adverb
Use so + adverb when emphasizing how an action happens: so slowly, so carefully, so quickly.
- 3
Use such with a singular countable noun
The usual pattern is such + a/an + adjective + singular countable noun: such a good idea, such an interesting story.
- 4
Use such with plural nouns
Do not use a/an with plural nouns: such friendly people, such difficult questions.
- 5
Use such with uncountable nouns
Do not use a/an with uncountable nouns: such useful information, such bad weather.
- 6
An adjective is not always necessary after such
Such can introduce a noun phrase without an adjective: such a surprise, such problems, such behavior.
- 7
Use so ... that and such ... that for results
Use so + adjective/adverb + that + clause or such + noun phrase + that + clause when the second part describes the result of the first.
- 8
Use so with much, many, few, and little
Use so many/few + plural countable noun and so much/little + uncountable noun to emphasize quantity.
Useful examples
I'm so tired today.
I'm very tired today.
So directly emphasizes the adjective tired.
Why are you speaking so quietly?
Why are you speaking this quietly?
Quietly is an adverb, so so is used before it.
It was such a beautiful day.
The day was extremely beautiful.
Such comes before the singular noun phrase a beautiful day.
She's such a helpful person.
She is a very helpful person.
A helpful person is a singular countable noun phrase.
They are such friendly people.
They are extremely friendly people.
People is plural, so there is no a or an after such.
We had such terrible weather on our trip.
The weather on our trip was really terrible.
Weather is uncountable, so such is used without a/an.
The coffee was so hot that I couldn't drink it.
The coffee was extremely hot, and as a result I couldn't drink it.
So emphasizes hot, while the that-clause expresses the result.
It was such an interesting book that I finished it in one day.
The book was so interesting that I finished it in a single day.
Such introduces the noun phrase an interesting book.
There were so many people that we couldn't find a seat.
The number of people was so large that we couldn't find anywhere to sit.
So many is used with the plural countable noun people.
We spent so much time looking for the hotel.
We spent a very large amount of time trying to find the hotel.
Time is uncountable in this meaning, so so much is correct.
He had so little money that he couldn't take a taxi.
He had very little money, so he couldn't take a taxi.
So little emphasizes a small amount of the uncountable noun money.
There were so few buses that we had to walk home.
There were very few buses, so we had to walk home.
So few emphasizes a small number of the plural countable noun buses.
I didn't expect the test to be so difficult.
I didn't think the test would be this difficult.
The negative sentence does not change the so + adjective pattern.
That was such a surprise!
That was a really big surprise!
An adjective is not required between such a and the noun.
How did the room get so messy?
How did the room become this messy?
So can emphasize an adjective in a question.
I've never seen such a crowded train.
I've never seen a train that was this crowded.
Such introduces the complete noun phrase a crowded train.
Common mistakes
- ❌ It is such cold today. ✅ It is so cold today. Cold is an adjective here, with no noun following it. Use so before the adjective.
- ❌ She is so a nice person. ✅ She is such a nice person. A nice person is a noun phrase, so use such before it.
- ❌ We have such many problems. ✅ We have so many problems. Many is used in the pattern so many + plural countable noun.
- ❌ He gave me so useful advice. ✅ He gave me such useful advice. Useful advice is a noun phrase. Advice is uncountable, so use such without a/an.
- ❌ It was such a expensive restaurant. ✅ It was such an expensive restaurant. A singular countable noun requires a/an in this structure. Expensive begins with a vowel sound, so an is required.
- ❌ The box was such heavy that I couldn't lift it. ✅ The box was so heavy that I couldn't lift it. Heavy is an adjective, so the correct result structure is so + adjective + that.
- ❌ There was so many traffic this morning. ✅ There was so much traffic this morning. Traffic is uncountable, so use much rather than many.
Learning tips
- Look at what follows: an adjective or adverb usually points to so, while a noun phrase usually points to such.
- For a singular countable noun, remember the word order: such + a/an + adjective + noun.
- Do not add a/an before plural or uncountable nouns after such.
- Learn so many, so much, so few, and so little as fixed quantity patterns.
- Do not choose so or such simply because you see that later in the sentence; examine the structure immediately after so or such.
- Remember that such does not always require an adjective: such a surprise and such problems are both possible.
- In natural speech, so can also have other functions, but this lesson focuses on its B1 use for degree and emphasis.
Practise this topic
Interactive exercises for this topic are coming soon.
PlannedRelated grammar
Related dictionary words
Frequently asked questions
How can I quickly decide whether to use so or such?
Look at what comes next. If you have an adjective or adverb on its own, use so: so tired, so slowly. If you have a noun phrase, use such: such a nice place, such friendly people.
Why do we say such a good idea instead of so a good idea?
Because a good idea is a noun phrase. The normal pattern before a singular countable noun is such + a/an + adjective + noun.
Do I always need a or an after such?
No. Use a/an only with a singular countable noun, as in such a nice car. Do not use it with plural or uncountable nouns: such nice cars, such useful information.
What is the difference between so difficult and such a difficult problem?
So difficult directly emphasizes the adjective difficult. Such a difficult problem emphasizes a noun phrase containing the adjective and the noun problem.
Why is it so many people and not such many people?
Many belongs to a special quantity pattern with so. The same principle applies to so much work, so few opportunities, and so little time.
Do I always need that after so or such?
No. Use that when you want to add a result: It was so cold that we stayed inside. Without a result clause, you can simply say It was so cold or It was such a cold day.
Can so and such be used in questions and negative sentences?
Yes. For example, Why are you so tired? and I didn't expect such a difficult question. The sentence type changes, but the basic choice between so and such remains the same.