The conjunction that is often left out. This is common in an informal style.
That can be left out after common reporting verbs like said, thought and suggested.
- She said that she was busy. OR She said she was busy.
- She suggested that we should wait. OR She suggested we should wait.
- I thought you weren’t interested. OR I thought that you weren’t interested.
That cannot be dropped after verbs like reply and shout.
- She replied that she wasn’t interested. (NOT She replied she wasn’t interested.)
- He shouted that he was coming. (NOT He shouted he was coming.)
That cannot be dropped after nouns.
- He agreed with my opinion that we should start again. (NOT He agreed with my opinion we should start again.)
That can be left out after adjectives in some common expressions.
- I’m glad that you are safe. OR I’m glad you are safe.
- It’s funny that he hasn’t come. OR It’s funny he hasn’t come.
- I was surprised that she won the prize. OR I was surprised she won the prize.
That can be left out after some common two-word conjunctions (e.g. so that, such…that, now that, provided that, considering that) in an informal style.
- Now (that) we have come so far, we may as well go all the way.
- Speak clearly so (that) we can hear you.
That as a relative pronoun
The relative pronoun that can be left out when it is the object in a relative clause.
- This is the woman that we were talking about. OR This is the woman we were talking about.