1. ‘So’ vs. ‘such’

‘So’ is used with adjectives (adj.) or adverbs (adv.).
‘Such’ is used with nouns (n.).

so + adj.	so + adv.	such + n.
He is so happy he has been invited to the party.	The girls finished their homework so quickly that their parents knew it was wrong.	His room is such a mess.
The movie was so disappointing.	The game sold so badly that the company went bankrupt.	The movie was such a disappointment.

2. ‘Such’ + (adj. + n.)

‘Such’ can be followed by adj. + n..
This means ‘really’.

Really	Such + adj. + n.
You have a really lovely house.	You have such a lovely house.
Her face has really delicate features.	Her face has such delicate features.
The house was a really big mess.	The house was such a big mess.
Studying history is a really big waste of time.	Studying history is such a big waste of time.

‘So + adj.’ can be used instead of ‘very + adj.’.
‘So + adj.” is slightly stronger than ‘very + adj.’.

‘So + adv.’ can be used instead of ‘very + adv.’.
‘So + adv.’ is slightly stronger than ‘very + adv.’.

Very + adv.	So + adv.
The team played very badly.	The team played so badly.
His students behaved very poorly.	His students behaved so poorly.
She spent money very freely on holiday.	She spent money so freely on holiday.

‘That’ has many uses.
One use is to replace ‘therefore’ (or other phrases that mean ‘therefore’) in sentences with ‘so + adj.’.

therefore phrase	that
I was so happy, therefore I danced.	I was so happy that I danced.
She was so angry, and because of that she hit him.	She was so angry that she hit him.

However, in these sentences ‘very’ cannot be used.

Right	Wrong
I was so happy that I danced.	I was very happy that I danced.
She was so angry that she hit him.	She was very angry that she hit him.
They were so tired that they fell asleep.	They were very tired that they fell asleep.
The woman was so rich that she bought her friend a car.	The woman was very rich that she bought her friend a car.

*Note: This rule is when ‘that’ means ‘therefore’. If ‘that’ means ‘because’ then ‘very’ is OK.

that = therefore	that = because
I was so angry, therefore I hit him	I was so angry because I hit him.
I was so angry that I hit him. (OK)	I was so angry that I hit him. (OK)
I was very angry that I hit him. (not OK)	I was very angry that I hit him. (OK)

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