A question mark (?) is used at the end of a direct question, which is a question you might ask someone in person:
- Are the books on the table?
- Do you have any vanilla ice cream left?
- Where do polar bears live?
- Who is at the door?
- When does class start?
A question mark is not used when the question is embedded inside of a statement. Let's look at some examples:
- I wonder whether Albert and Henry are at home. (Direct question: "Are Albert and Henry at home?")
- Isla called her mechanic to confirm how much the car repair would cost. (Direct question: "How much would the car repair cost?"
- The chef wants to know if you are allergic to nuts. (Direct question: "Are you allergic to nuts?")
These embedded questions are called indirect questions and require a period at the end.
To determine whether a question is direct or indirect, you simply have to check whether the question is "blended" into the sentence (indirect question) or one that you might ask someone in person. Direct questions are always standalone sentences or separated off by punctuation.
- The paleontologist dedicated his life to answering just one question: did Tyrannosaurus Rex have feathers? (Even though the question is part of the sentence, it's separated off by a colon. It's also a question you could ask directly to someone else in person. Therefore, the question is direct and requires a question mark.
- The paleontologist dedicated his life to answering just one question—did Tyrannosaurus Rex have feathers? (Same as the above except a dash is used instead of a colon)
- The paleontologist dedicated his life to figuring out whether Tyrannosaurus Rex had feathers. (Indirect question)
Another important difference between direct questions and indirect questions is their word order:
Direct questions have a verb-subject word order. Indirect questions have a subject-verb word order.
Let's compare:
Direct: Is he in his room? (The verb "is" comes before the subject "he")
Indirect: I asked if he is in his room. (The subject "he" comes before the verb "is")
For direct questions that require a helping verb (a form of to be, to have, or to do), it is the helping verb that comes before the subject:
Direct: Where do polar bears live? (The helping verb "do" comes before the subject "polar bears")
Indirect: I wonder where polar bears live. (The subject "polar bears" comes before the verb "live")
Let's finish this lesson off with an example question you might encounter:
In 2002, biologists Ray Smith and Janet Wollaston set out to study how ______________ What they discovered after tracking the body temperatures of 18 wild goats over four months is that their horns are instrumental in helping them dissipate heat.
A) do goats survive during a drought?
B) goats survive during a drought?
C) do goats survive during a drought.
D) goats survive during a drought.
If we look at where the blank line is placed (after the word "how"), it's obvious that the missing question is one that's embedded in the sentence; it's not separated off by any punctuation. Therefore, the answer must be an indirect question. Since indirect questions end in a period, we can eliminate answers A and B, both of which end in a question mark.
Since indirect questions have a subject-verb word order, we can also eliminate answer C, which puts the helping verb "do" before the subject "goats". The answer is then D.