Here are suitable noun clauses to complete each of the sentences provided. Noun clauses often begin with words like 'that', 'what', 'who', 'whom', 'which', 'when', 'where', 'why', and 'how'. They can function as a subject, an object, or a complement.
The teacher believed that the students had studied hard for the exam.
In this sentence, 'that the students had studied hard for the exam' is the noun clause acting as the object of the verb 'believed'.
Do you know what the homework assignment is for tomorrow?
Here, 'what the homework assignment is for tomorrow' is the noun clause acting as the object of the verb 'know'.
Can anyone guess who will win the competition?
'Who will win the competition' is the noun clause that functions as the object of the verb 'guess'.
I wondered why the meeting was canceled.
This sentence uses 'why the meeting was canceled' as the noun clause functioning as the object of the verb 'wondered'.
I told you that the book is due next week.
In this example, 'that the book is due next week' is the noun clause functioning as the object of the verb 'told'.
You should remember where you left your keys.
'Where you left your keys' is the noun clause that serves as the object of the verb 'remember'.
No one knows how the problem started.
Here, 'how the problem started' is the noun clause acting as the object of the verb 'knows'.
Nobody could explain why the results were unexpected.
'Why the results were unexpected' is the noun clause functioning as the object of the verb 'explain'.
These examples show how noun clauses can be used to provide additional information or complete thoughts in sentences. They are an essential part of forming complex sentences in English.