That

So + adjective/adverb + that clause: ‘I’m so tired that I can’t keep awake.’

Use so that to express purpose (NOT that): ‘The burglars put off all the lights so that they wouldn’t be seen.’

When making a comparison, use as/so … as (NOT as/so … that): ‘It’s as hard to get into university today as it was ten years ago.’

When giving a reason for something, use since or as (NOT that): ‘Instead of cooking, why don’t we get a take-away, especially as it’s so late.’

That is used to introduce an identifying relative clause (one, which identifies, defines, or restricts the preceding noun): ‘The woman that is sitting behind us is Tom’s music teacher.’

To make a precise reference to a previously mentioned action, use do so (NOT do that): ‘I asked him to take his feet off the seat but he refused to do so.’