All the books are not useful. Which of the following has the same meaning as this sentence?
In that school, English is compulsory for all students, but French and Russia are ____ .
––Why didn’t you come to the party? ––I had meant _____, but something unexpected happened.
We should discuss the plan _____ before we work it out.
Mom used only half of the money, the rest of which ______ saved for other purposes.
As he reached _____ back door, Jack saw _____ strange sight.