Ответ:

1. Will Trevor and Laura have lived here for four years next April?

Trevor and Laura won’t have lived here for four years next April.

2. Will they have finished it until midnight?

3. Will I have read this book by the time it’s due back to the library?

I won’t have read this book by the time it’s due back to the library.

4. Will my husband have finished his work by half past eight?

My husband won’t have finished his work by half past eight.

5. Will we have finished dinner by then?

We won’t have finished dinner by then.