John wants to be an astronaut in the future.
I know(that )John wants to be an astronaut in the future.
Does Mike want to go to Qingdao this summer?
Daniel is still not sure if /whether Mike wants to go to Qingdao this summer
Are there any shopping centres on Mars?
Millie is wondering if / whether there are any shopping centres on Mars.
The moon moves around Earth.
Our terther told us that the moon moves around Earth.
Have you packed your things for the trip?
Jim's mother asked him if/ whether he had packed his things for the trip.
Is gravity a problem for the astronauts who land on the moon?
Could you tell me if / whether gravity is a problem for the astronauts who land on the moon.