1. Indirect questions: the polite and friendly questions

2. There are a number of introductory phrases that can be used to begin an indirect question. For example:
Do you know + …statement (s+v)…?
Can/Could you tell me +…statement…?
Do you have any idea+…statement…?
I’d like to know +…statement…
I wonder +…statement…
Please tell me+…statement
Tentative situation (unconfirmed)
Can/Could you tell me if/whether +…statement?
Can you let me know if/whether + …statement?
Has she told you if/whether+…statement?
I wonder if+…statement

3. For example What is the answer? (direct question)
Do you know what the answer is?
Do you know where the post office is?
Could you tell me if it’s OK to use mobiles here?
Do you know how much it costs?
I’d like to know how much it costs
I wonder who knows him.
I wonder if/whether they are expensive.
I wonder if she likes me.

4. It means that Yellowstone Park is a beautiful place, but is also very dangerous because of the volcanic activity.
It’s about 72 kilometres across, i.e. from one side to the other and about 13 kilometres thick.
Because the explosion would be enorous but nobody can predict exactly how bad it would be.
No, because nobody was there the previous time it exploded, so they don’t know what the warning signs are.
Because there are already all the usual warning signs (earthquakes, etc.) but nothing has happened yet.
Because more than three million people visit it each year, the roads are narrow which slows traffic down, and it can take half a day to drive across the park.