Did he invent the light bulb? "I don't know"
I don't know if (whether) he invented the light bulb.
She asked me if was raining outside.
She asked me if it was raining outside.
Where is the Calle 13 concert going to be? "My grandma was wondering"
My grandma was wondering where the Calle 13 concert is going to be.
How long have you ridden your Harley Davidson? "I wonder"
I wonder how long you have ridden your Harley Davidson.
They are not sure if to invite her to the party.
They are not sure whether to invite her to the party.
How long is the journey to Mexico City? "I'm not sure"
I'm not sure how long the journey to Mexico City is.
Why shouldn't you have drunk the tequila last night? 'Do you know?'
Do you know why you shouldn't have drunk the tequila last night?