This document discusses how noun clauses are used to replace yes/no questions. It states that if is usually used to introduce a noun clause when changing a yes/no question into a noun clause. It also notes that whether has the same meaning as if and can be used instead. Examples are provided showing the yes/no question, the corresponding noun clause using if, and sometimes with the addition of "or not" at the end of the clause.

1. 14-3 NounClauses That Begin If
or Whether
Page 376

2. Whenayes/no
questionischanged
toanounclause,ifis
usuallyusedto
introducetheclause.
Information
Question
Noun Clause
Is Eric at home? I don’t know if Eric is at home.
Does the bus
stop here?
Do you know if the bus stops
here?
Did Alice go to
Chicago?
I wonder if Alice went to Chicago.

3. Whenifintroducesa
nounclause,the
expressionornot
sometimescomesatthe
endoftheclause.
Information
Question
Noun Clause
Is Eric at home? I don’t know if Eric is at home or
not.
Does the bus
stop here?
Do you know if the bus stops here
or not?
Did Alice go to
Chicago?
I wonder if Alice went to Chicago
or not.

4. Whetherhasthe
samemeaningasif.
Information
Question
Noun Clause
Is Eric at home? I don’t know whether Eric is at
home or not.
Does the bus
stop here?
Do you know whether the bus
stops here?
Did Alice go to
Chicago?
I wonder whether Alice went to
Chicago (or not).