We can use clauses with that:
• after verbs of thinking:
I hope that you will enjoy your holiday.
She didn’t really think that it would happen.
I knew that I had seen her somewhere before.
• after verbs of saying:
They admitted that they had made a mistake.
She argued that they should invest more in the business.
The children complained that they had nothing to do.
Note: tell and some other verbs of saying almost always have an indirect object (see clauses, sentences and phrases). There are also some fixed expressions with tell such as tell the truth, tell a lie, tell a story, tell it like it is.
We tried to tell them that they should stop what they were doing.
The police informed everybody that the danger was over.
• as postmodifiers after nouns to do with thinking or saying:
He made a promise that he would do all he could to help.
I had a funny feeling that something was wrong.
• after some nouns to say more about the noun:
She pointed out the danger that they might be left behind.
There was a chance that we would succeed
Note: We often use a that clause to define one of these nouns after the verb be :
The danger is that we will be left behind.
The fact is that it is getting very late.
• after some adjectives which describe feelings to give a reason for our feelings:
I am sorry that you can’t come.
Everybody was pleased that the danger was past.
It is lucky that you were able to drive us home.
NOTE: We can always use a clause without the word that:
They admitted [
that] they had made a mistake.
The police informed everybody [
that] the danger was over.
I am sorry [
that] you can’t come.
There was chance [
that] we would succeed.