No, if a sentence ends with a question mark, there is no need for an additional question mark at the end.
If the sentence is a question then it does.
You can use a period (.), an exclamation mark (!), or a question mark (?) to end a sentence.
No, not every sentence with "if" has to end with a question mark. The use of a question mark at the end of a sentence depends on whether the sentence is asking a question or stating a fact.
A sentence with a question mark at the end is called an interrogative sentence.
Yes, a question mark should be placed at the end of a topic that asks a question to indicate that it is seeking a response from the reader or listener.
Question mark (?) is put at the end of a sentence to indicate that it is a question.
If the sentence is a statement it has to end in a period. If it is a question it would end in a question mark (?) and if the sentence indicates stong feeling it would end in an exclamation mark (!)
An interrogative sentence ends with a question mark.
A Question Mark.
A question mark is a punctuation mark used to end an interrogatory sentence.
If it has a question "?" mark at the end of the sentence.