This time next month Elizabeth ________ (still / to work) in Spain.
will still have worked
will still work
still works
will still be working
We use the Future Continuous to talk about unfinished actions which will be in progress in the future.
_______ (you / to stay) here until we come?
Do you stay
Are you going to stay
Will you have stayed
Will you be staying
We use 'be going to' for intentions and plans. This expression refers to the present situation: we know the circumstances and according to them we make the intention.
I don't care what it means to you but you ______ (to throw) this old table away now.
throw
are going to throw
will throw
are to throw
We use 'be to' to express strong obligation in the future. This construction is very similar to the meaning of 'must'.