Could you tell me where I should sign my name?

---> Could you tell me where (a)   my name ?

I have no idea when we should leave for the bus.

---> I have no idea when (a)   for the bus.

We’re not sure where we should hang the painting.

---> We're not sure where (a)   the painting.

He wondered how he could tell this news to his parents.

---> He wondered how (a)   this news to his parents.

They can’t decide who should go first.

---> They can't decide who (a)   first.