There are some verbs and adjectives, however, that do not refer to saying or thinking, but that are followed by that-clauses because they refer to actions relating to facts: for example, checking or proving facts.
He checked that both rear doors were safely shut.
Research with animals shows that males will mother an infant as well as any female.
Here is a list of verbs that are not verbs of speech or thought, but can be followed by a that-clause:
arrange
check
demonstrate
determine
ensure
indicate
pretend
prove
require
reveal
show
Note that determine can also be a verb of thought, and reveal can also be a verb of speech. See paragraphs 7.30, 7.38, and 7.48.
Arrange and require are used with a that-clause containing a modal or a subjunctive. Arrange can also be used with a to-infinitive.
They had arranged that I would spend Christmas with them.
They’d arranged to leave at four o’clock.
Demonstrate, prove, reveal, and show can also be followed by a clause beginning with a wh-word that refers to a circumstance involved in a fact.
She took the gun and showed how the cylinder slotted into the barrel.
Prove, require, and show can also be used in the passive followed by a to-infinitive.
No place on Earth can be shown to be safe.
If you want to mention another person involved in these actions, you can put an object after show, use to after demonstrate, indicate, prove, and reveal, and use with after arrange and check.
The children’s attitude showed me that watching violence can affect a child’s behaviour.
This incident proved to me that Ian cannot be trusted.
She arranged with the principal of her school to take some time off.
8.118 If you want to say that something happens, that something is the case, or that something becomes known, you can use a that-clause after happen, transpire, or emerge. The subject of the main clause is impersonal it.
It often happens that someone asks for advice and does not get it.
It just happened that he had a client who rather liked that sort of thing.
It transpired that there was not a word of truth in the letter.
It emerged that, during the afternoon, she had gone home unwell.
Note that the that-clause must be introduced by that.
adjectives with nominal that-clauses: I was afraid that he would fall
8.119 There are many adjectives that can be followed by that-clauses when they come after a linking verb, usually be.
mentioning the cause of a feeling
8.120 If you want to say what causes someone to have a particular feeling, you can mention the cause of the feeling in a that-clause after an adjective describing the feeling.
Everybody was sad that she had to return to America.
I am confident that I shall be able to persuade them to go.
I was worried that she’d say no.
Here is a list of adjectives describing feelings:
afraid
angry
anxious
confident
frightened
glad
happy
pleased
proud
sad
sorry
surprised
upset
worried
saying what someone knows
8.121 If you want to say that someone knows something, you can say what they know in a that-clause after an adjective such as aware or conscious.
He was aware that he had eaten too much.
She is conscious that some people might be offended.
Here is a list of adjectives indicating knowledge:
aware
certain
conscious
convinced
positive
sure
unaware
Aware is occasionally used with a that-clause beginning with a wh-word.
None of our staff were aware what was going on.
commenting on a fact
8.122 If you want to comment on a fact, you can use an adjective describing the fact followed by a that-clause. The linking verb has impersonal it as its subject.
It was sad that people had reacted in the way they did.
It is true that the authority of parliament has declined.
It seems probable that the world can go on producing enough food for everyone.
Here is a list of adjectives used to comment on facts:
apparent
appropriate
awful
bad
clear
essential
evident
extraordinary
fair
funny
good
important
inevitable
interesting
likely
lucky
natural
obvious
plain
possible
probable
sad
true
unlikely
After a few adjectives, a clause beginning with a wh-word can be used.
It’s funny how they don’t get on.
It was never clear why she took a different route that night.
For more information, see paragraph 9.43.
commenting on a fact or idea
8.123 That-clauses can be used after be to refer to a fact or idea. The subject is usually one of the nouns listed in paragraph 7.86.
The fact is that a happy person makes a better worker.
The answer is simply that they are interested in doing it.
The most favoured explanation was that he was finally getting tired.
Our hope is that this time all parties will cooperate.
8.124 In formal English, that-clauses are sometimes used as the subject of a verb, when people want to comment on a fact.
That she is not stupid is self-evident.