Дополните предложения, содержащие косвенные вопросы:1. Im not really sure

Дополните предложения, содержащие косвенные вопросы:
1. Im not really sure ___________________.
a. whether the plane will be late b. will the plane be late
2. Do you remember ______________?
a. where you put the car keys b. where did you put the car keys
3. Can you tell me ________________?
a. did she buy a book b. whether she bought a book